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The Wettest Year Ever in the United States

Data source: National Centers for Environmental Information 2016c.

Figure 1 Data source: National Centers for Environmental Information 2016c.

Last year was the wettest year ever in the Contiguous United States, according to data from the National Centers for Environmental Information (NCEI). In Figure 1 the blue bars show the percentage of the country that was very wet (wettest 10% of years), and the red bars below the line show the percentage of the country that was very dry (driest 10% of years). In 2015, 36.15% of the country was very wet, the largest percentage since record keeping began in 1895. None of the country was very dry, which has happened 3 other times since record keeping began.






Data source: National Centers for Environmental Information 2016b.

Figure 2 Source: National Centers for Environmental Information 2016b.

Precipitation varies from place-to-place, however. Figure 2 show precipitation across the country by NCEI Climate Division. It was drier than average in parts of California, the Northwest, and New England. Much of the rest of the country was wetter than average. Regions in Texas, Oklahoma, Kansas, Iowa, and North Carolina had their wettest year ever. On this map, the dark green (wettest year ever) and medium green areas (much above average) correspond to the very wet percentage in Figure 1.







Data source: National Centers for Environmental Information 2016a.

Figure 3 Source: National Centers for Environmental Information 2016a.

In Missouri, 2015 was the 4th wettest year since 1895. Starting in 1981, 21 out of 35 years have seen above average precipitation. The blue line shows the linear trend since 1895. The trend equates to a 0.25 inch per year increase each decade. Most future climate models show the Eastern United States getting wetter, and the Western United States getting drier. Missouri is near the boundary, and climate modeling has had a lot of uncertainty. At this point, the trend is towards wetter.

There is considerable seasonal variation, however. It is hard to make sense out of the trend for each season. If one half of the year was trending more than the other, I would understand it. But the alternating pattern below is more difficult to understand, and it is possible that the trend is being controlled by individual outlier years:

Winter (Jan- Mar): -0.02 inches/decade
Spring (Apr – Jun): +0.08 inches/decade
Summer (Jul – Sep): -0.03 inches/decade
Fall (Oct – Dec): +0.22 inches/decade

Source: National Centers for Environmental Information 2016b.

Figure 4 Source: National Centers for Environmental Information 2016b.

Figure 4 shows precipitation for the climate divisions in Missouri for 2015. Precipitation throughout the state was well above average everywhere, but it was wettest across Southern Missouri, which received more than 60 inches. The rainfall that resulted in record flooding in some areas occurred in late December. The heaviest band of rainfall occurred along a line almost directly over Interstate 44 from the southwest corner of the state through St. Louis. (Figure 5)








Source: National Centers for Environmental Information.

Figure 5 Source: National Centers for Environmental Information 2016a.

When I look at precipitation, I look at two other regions of the country besides Missouri. First, I look at the Northern Rockies and Great Plains. I look there because it is the source of the Missouri River, the largest source of potable water in Missouri. Figure 6 shows that 2015 was a moderately above average precipitation year in this region. The blue line shows the trend, which has been increasing by 0.06 inches per decade. Compare the less than 20 inches of precipitation in this region with the more than 60 inches across Southern Missouri. This is a drier, but not desert, region.





Source: National Centers for Environmental Information 2016a.

Figure 6 Source: National Centers for Environmental Information 2016a.

The other region I look at is California, because of my interest in the drought there. Figure 6 shows California precipitation through 2015. It was the 13th driest year since 1895. The trend shows that California has been receiving 0.05 inches less precipitation each decade since 1895. In December, a strong El Niño weather pattern began bringing increased precipitation to California. It was too late to drastically affect the statistics for 2015, but 2016 may be a better water year there.


National Centers for Environmental Information. 2016a. Climate at a Glance. Data retrieved 1/10/16 from http://www.ncdc.noaa.gov/cag/time-series/us.

National Centers for Environmental Information. 2016b. National Temperature and Precipitation Maps. Data retrieved 1/9/16. http://www.ncdc.noaa.gov/temp-and-precip/us-maps/12/201512#us-maps-select. Select Year = 2015, Month = December, and Timescale = 12-Month.

National Centers for Environmental Information. 2016c. U.S. Percentage Areas (Very Warm/Cold, Very Wet/Dry). Data downloaded 2016-01-11 at http://www.ncdc.noaa.gov/temp-and-precip/uspa/?area=wet-dry&year=2015&month=12. Select “VeryWet/Very Dry” and “December.”

National Weather Service, St. Louis, MO, Weather Forecast Office. 2016. December Historic Rainfall and Flooding Event Review. http://www.weather.gov/lsx/12_26_2015.

2015 the Second Warmest Year Ever in the USA

Data source: National Centers for Environmental Information 2016b.

Figure 1. Data source: National Centers for Environmental Information 2016b.

Weather data for 2015 has been posted on the Climate at a Glance data portal operated by the National Centers for Environmental Information (NCEI). Figure 1 shows average temperature data for the contiguous 48 states. Florida, Montana, Oregon, and Washington had the warmest years on record. The Southeast, Northern Plains, and West were much warmer than average. States along a line running from Texas to Maine were warmer than average, but less so than other areas. The number on each state shows what rank, from coolest to warmest, 2015 was for that state.

Across the country as a whole, the average temperature for 2015 was 54.40°F, the second warmest year since they began keeping records in 1895. The warmest occurred in 2012: 55.28. In Missouri, the average temperature was 55.8°, the 22nd warmest year since 1885. The warmest was 2012 at 58.6°F.


Figure 2. Data source: National Centers for Environmental Information 2016a.

Figure 2. Data source: National Centers for Environmental Information 2016a.

Figure 2 shows the national temperature trend since record keeping began in 1895. The red line at the top shows the average maximum temperature for each year, the orange line in the middle shows the average average temperature for each year, and the blue line at the bottom shows the average minimum temperature for each year. The thin straight lines show the trends for each. The trend lines slope upwards about 2° since 1895.

It isn’t easy to see, but a look at the equation for each trend line shows that the slope of the average minimum temperature is steepest, followed by the slope for the average average temperature, with the slope for the average maximum temperature being smallest. The differences are not large, but it suggests that climate change is causing the average minimum temperature to increase faster than the average maximum temperature. The finding is consistent with projections for climate change: as the temperature warms, the atmosphere can hold more humidity. The humidity reduces the amount of cooling that occurs at night.

Figure 3. Data source: National Centers for Environmental Information 2016a.

Figure 3. Data source: National Centers for Environmental Information 2016a.

Figure 3 shows the Missouri temperature trend. The red line at the top shows the average maximum temperature, the orange line in the middle shows the average average temperature, and the blue line at the bottom shows the average minimum temperature. The thin straight lines show the trends.

The trend lines show that in Missouri, the average maximum temperature has hardly changed, while the average minimum temperature has increased about 1°F. The change in Missouri is less than the average nationwide change, and the reason is, again, humidity. Missouri is a humid state, and it takes more energy to change the temperature here than it does in a dry state.

Because I have been following the water situation in California, I will note that the average temperature there in 2015 was 60.8°F, the second highest since record keeping began. You may have seen news stories about the recent rain and snow in California. It is starting off to be a good water year for them. I’ll look at their water situation in more detail a little later in the winter.

To summarize, 2015 was warmer than average across the entire contiguous United States. Along a line of states running from Maine to Texas it was somewhat warmer than average, but less than the rest of the country. In the Southeastern and Northwestern corners of the country, it was the hottest year on record.

I’ll look at precipitation during 2015 in the next post.


National Centers for Environmental Information. 2016a. Climate at a Glance. Data retrieved 1/10/16 from http://www.ncdc.noaa.gov/cag/time-series/us.

National Centers for Environmental Information. 2016b. National Temperature and Precipitation Maps. Data retrieved 1/9/16. Select Year = 2015, Month = December, and Timescale = 12-Month.

2014 Was the Hottest Year Ever Worldwide

2014 was the hottest year ever worldwide, according to the State of the Climate in 2014 report by the American Meteorological Society. This is a report that came out in July, 2015, and I’m just catching up to it now. I will summarize a few of the many findings.

Figure 1: Global Surface Temperature Anomalies, 2014. Source: Blunden & Derek 2015.

Figure 1: Global Surface Temperature Anomalies, 2014. Source: Blunden & Arndt 2015.

Figure 1 shows how much 2014 temperatures around the globe varied from the average temperature for that location (reference years 1981-2010). The yellow and red areas were warmer than average, the blue areas cooler. Gray represents areas for which there is not enough data to make a characterization. You can see that the map has many more yellow and red areas than blue. Across 5 different data sets, the temperature over land was .39°C hotter than average, the temperature over ocean was .22°C hotter than average, and for the whole world was .26°C hotter than average.


Figure 2: Global Surface Temperature Trends. Source: Blunden & Derek 2015.

Figure 2: Global Surface Temperature Trends. Source: Blunden & Arndt 2015.

Figure 2 shows the trend in global temperatures from 1880 to 2014. The top two graphs represent different analyses of both land and ocean, the middle two graphs represent different analyses of land only, and the bottom two represent different analyses of ocean only. All of the charts show a consistent and continuing warming trend that began in 1910, and perhaps earlier than that.

One of the ways global warming has its effect is by increasing the number of “warm” days. What is a “warm” day? That’s actually a bit involved to explain. Here goes: to start with, study the 30-year period from 1961 to 1990. For each date – each February 2nd, for instance – there is an average temperature on that date for each year. List the average temperatures on February 2 for all of the years. Since there are 30 years, there will be 30 average temperature. Determine the hottest 10% of them. In this case, since there are 30, the hottest 10% would be the hottest 3. Look at the lowest of the 3. That becomes the cut-off temperature.

Figure 3: Global Warm Day Anomalies, 2014. Source: Blunden & Derek 2015.

Figure 3: Global Warm Day Anomalies, 2014. Source: Blunden & Arndt 2015.

If the temperature on February 2 in 2014 is hotter than the cut-off, it counts as a “warm” day. Now do that same procedure for every date in the year. Now count the number of “warm” days in 2014. Now divide that number by the total number of days in 2014 and multiply by 100 to yield a percentage. Subtract 10% from the calculated percentage to yield the anomaly. That is what is shown in Figure 3.

Here’s another way to say it: in Figure 3, northeastern Europe and northwestern Russia ar colored dark red. That means they have an anomaly of 10. That means that 20% of the days in 2014 were hot enough to fall in the range that defines the hottest 10% of days in the reference period (1961-1990).

You can see that in Figure 3 there are large blobs of red over Australia, Southeast Asia, China, parts of India, Europe, Northeastern Russia, Greenland, and western North America. That means that all these regions had an increase in the number of warm days. Middle and Eastern North America, on the other hand, had fewer.

In the summer a “warm” day might indicate that it was extremely hot, which is hazardous. During the winter, on the other hand, it might indicate that the day was above freezing. In regions that depend on their snowpack to last into the summer, winter melting can be a problem.

Figure 4: U.S. Temperature Anomalies, 2014. Source: Blunden & Derek 2015.

Figure 4: U.S. Temperature Anomalies, 2014. Source: Blunden & Arndt 2015.

For the United States the situation was a bit different. Figure 4 shows the pattern. A winter outbreak of frigid winter weather kept average temperatures in the central parts of the country down, and to a lesser extent the east as well. Throughout the West it was hotter than average, with 2014 being the hottest year on record in California, Arizona, Southern Nevada, and Western Oregon.





Figure 5: U.S. Temperature Trend. Source: Blunden & Derek 2015.

Figure 5: U.S. Temperature Trend. Source: Blunden & Arndt 2015.

Figure 5 shows annual mean temperatures for the contiguous United States for 1895-2014. There are some pretty wide swings from year to year, but the pattern shows a clear trend of increasing temperature of about 2°.

The report is not fine-grained enough to speak directly to the situation in Missouri. Still, it shows that the worldwide trend with regard to temperature continue to be upward. Many other climate variables are also reported, and most of them continue the trends that have been in place for the last several decades. All are consistent with what would be expected as a result of global warming.

I’m writing this post in early January, 2016. Climate data for 2015 should post-up on Climate at a Glance during January, so hopefully by the time this post goes live, I’ll be able to follow up with information about the USA and Missouri.


Blunden, Jessica and Derek Arndt (eds.) 2015. “State of the Climate in 2014.” Bulletin of the American Meteorological Society, 96 (7) Special Supplement. Downloaded 1/4/16 from http://journals.ametsoc.org/doi/abs/10.1175/2015BAMSStateoftheClimate.1.

Record Low Snowpack in California

If you follow this blog, you know that I have been watching the drought in California rather closely. New data is in, and it doesn’t look good.

Precipitation is seasonal in California. The winter is the wettest part of the year, the summer is bone dry in most locations. California uses reservoirs to collect water during the winter and provide it during the summer. California’s largest “reservoir” is its mountain snowpack. This accumulates during the winter, then melts gradually during the spring and summer. The runoff recharges California’s aquifers, it keeps rivers flowing, and it is collected into man-made reservoirs.

Snow Survey PhotosBecause it is so important, California measures its mountain snowpack. Because snow can be light and fluffy or heavy and wet, the measurement they use is the water equivalent in inches. Think of it as the depth of water that would result if you melted the snow. A bucket may have 10 inches of snow in it, but if you melt it, the water would only be a 1-4 inches deep.

The water content of the snowpack generally peeks in early April, thus the April measurements are the most important. The California Snowpack Survey for April 1, 2015, found that the snowpack held the equivalent of only 1.4” of water, when the historical average is 28.3”. At one of the measuring sites, for the first time ever, there was no snow at all, the ground was bare (Phillips). (See photos at right.) The bottom line is that California’s most important reservoir is holding about 5% of the water it usually holds.

(Click photos for larger view.)

Dec-Feb Precip ChartThere are two basic reasons for the lack of snowpack. First, less precipitation is falling. Data from March 2015, has not been posted, but the chart at right shows December – February precipitation in California for the past 10 years. Precipitation has been significantly below average for each of the last 4 years. I suspect that when March data is posted, 2015 will look much worse than it does in this chart.


Dec-Feb Temp Chart.xlsxThe second reason is that temperatures have risen. The second chart at right shows the data. Warmer temperatures, especially over the last 2 years, mean that precipitation that would have fallen as snow instead fell as rain. And some of the snow that did fall melted right away.

This is the 4th year of severe drought in California. The state has just put in place the first mandatory water conservation requirements in its history. The following links will take you to a series of articles that the New York Times has been running on the new requirements, and on how the state is coping with the drought.





For the California Snowpack Survey press release: California Department of Water Resources. Sierra Nevada Snowpack Is Virtually Gone; Water Content Now is Only 5 Percent of Historical Average. http://www.water.ca.gov/news/newsreleases/2015/040115snowsurvey.pdf.

The press release contains a link to photos of the Phillips snowpack survey site. If the link doesn’t work, here is the url: https://d3.water.ca.gov/owncloud/public.php?service=files&t=e5a72c13a0d5f1b4f8b49e584a0d8da7.

The precipitation and temperature data for California were obtained using the National Oceanographic and Atmospheric Administration’s Climate At A Glance Data Portal, http://www.ncdc.noaa.gov/cag/time-series/us.

Don’t Look Now…

Don’t look now, but California has gone back to a dry pattern. Major storms there in December made the news, and some people I know were talking as if the drought there was broken.

Not so fast. One of the heartbreaking things about droughts is that they offer you hope, then take it back away. It rained in Oklahoma during the Dust Bowl, but every time it was not enough, and every time the drought returned full force.

CA Precipitation Chart 2015-01During January, the drought returned in California. NOAA data isn’t yet available for the whole state as a single aggregate. In the chart at right are precipitation totals for six California cities that span the state from Redding in the far north to San Diego in the far south. The blue bars represent normal precipitation for January, the red bars actual precipitation during January 2015. The whole state has been dry, and in the north, where they get most of their precipitation, it basically didn’t rain at all.

In California, the snowpack is all important, for it releases its moisture slowly as it melts, providing water during the hot, dry summer. The most recent snowpack survey was conducted 1/29/2015 by the California Water Department. The water content of the snowpack was just 25% of the historical average for this date.

The final snowpack accounting doesn’t occur until April, making it possible that heavy precipitation in February and March could build the snowpack to normal levels. However, the press release concludes that it is “likely that California’s drought will run through a fourth consecutive year.”

It is unclear at this time exactly how the drought will affect Missouri. One possible effect would be increased food prices. As I have previously noted, California produces roughly half of the nation’s fruits and vegetables.


Precipitation data for 6 California cities were found on the National Weather Service Forecast Office for each city. On the home webpage for each forecast office, in the left column select “Climate – Local.” On the resulting page, select the Daily Climate Report for the desired location for January, 31, 2015.

For the California snowpack data: “Scant Precipitation, Little Precipitation, Produce Weak Snowpack”. 1/29/2015. California Department of Water Resources. http://www.water.ca.gov/news/newsreleases/2015/012915snowpack.pdf.

2014 Hottest Year On Record

What timing! Two weeks ago I put up a blog post saying that the January cold snaps this year and last year didn’t mean that it was really as cold as it seems. Then, two days later (1/17/15), the temperature in St. Louis topped out at 63°F, just to prove my point. And then, on 1/19/15, the National Climate Data Center (NCDC) published temperature data for calendar year 2014.

Anomalies are shown in °C.

Anomalies are shown in °C.

It turns out that globally, 2014 was the hottest year since record keeping began in 1880. The first chart at right shows the data. The NCDC publishes this data as temperature anomalies. That is, they compute the average temperature for the 20th Century (1901-2000), and show how much each year differed from the average. The graph shows a very clear trend from cooler to warmer, and this is the trend that climate scientists interpret as global warming.

The global temperatures are shown in degrees Celsius, because those are the units used around the world. The coldest year was 1911, at an anomaly of -0.44°C. The warmest was last year, 2014, with an anomaly of 0.69°C. Converting Celsius to Fahrenheit, 2014 was about 2.03°F warmer than 1911. It’s not a very big difference, but if you consider that it is spread over the entire surface of the earth, it represents a LOT of energy!

Anomalies are shown in °F.

Anomalies are shown in °F.

For the contiguous United States, 2014 was warmer than average, but not extraordinarily warm. That wobbly Polar Vortex I wrote about in the previous post kept the temperature down in some parts of the country (like Missouri, see below). The data is shown in the second chart at right. The temperature anomalies are shown in degrees Fahrenheit, because those are the units we use in the USA. The anomaly in 2014 was 0.53°F, making it the 34th warmest year on record.

For Missouri, 2014 was cooler than average, with the temperature anomaly of -1.6°F, making it tied for the 9th coolest year on record.

The data provide a great example that you can’t judge what’s going on around the globe by what is happening locally.

Anomalies are shown in °F.

Anomalies are shown in °F.

It would be so easy to get the idea that global warming had abated if you only considered Missouri or the Midwest. But you’d be wrong.


Climate At A Glance data portal, National Atmospheric and Oceanographic Administration.http://www.ncdc.noaa.gov/cag.

Wobbly Polar Vortex

In some years, January temperatures in Missouri are “pretty-all-the-same.” Other years, they are all over the place (see previous post). Why?

One reason is because of a wobbly Polar Vortex.


A wobbly Polar Vortex. Let me explain.

We’re familiar with low air pressure systems from the nightly weather report. Often, they bring storms. Around low pressure systems, the wind flows in a counterclockwise circle, called a cyclone. A tornado is a small, very intense cyclone around a low pressure area, while a hurricane is a large cyclone around a low pressure area. Both tornadoes and hurricanes are intense, but relatively short-lived.

Thousands of feet above the Arctic sits a more-or-less permanent low pressure area attended by a cyclone. But instead of encompassing an area of a mile or less, as does a tornado, or of a hundred miles or so, as does a hurricane, the cyclone above the Arctic encompasses several million square miles. The air rushes counterclockwise, circling the North Pole at up to 100 miles per hour.

Because the system is a low pressure system, and because the air rushes around it in a coherent circle, this cyclone has the effect of containing the frigid air of the Arctic. This system of low pressure, cold air, and counterclockwise wind is called The Polar Vortex. For this blog post, what we need to know about it is that it contains the frigid arctic air, preventing it from spreading southward.

Wobbly Polar Vortex MapIn 2014, there was a significant weakening of the Polar Vortex. The low pressure was less low, and the speed of the wind rushing counterclockwise around the North Pole slowed. The result was that the Polar Vortex was less able to prevent blasts of cold arctic air from pushing their way south. The map at right shows the weakened, wobbly Polar Vortex of January 2014, compared to a normal Polar Vortex of November 2013. The white line is the boundary of the vortex. Notice how the boundary in November 2013 was smooth and extended about as far south as the border between Canada and the USA. But in January 2014, it was full of bulges and intruded well down into the Midwest.

That’s cold air, and when it was over Missouri, we had frigid temperatures. But as the cold air rotated away from Missouri flowing counterclockwise around the North Pole, the boundary of the Polar Vortex retreated northward. Warm air replaced the frigid air, and we had warm temperatures. These alternating air masses caused the wild swings in temperature.

I don’t think anybody knows for sure why the Polar Vortex suddenly weakened – from November 2013 to January 2014 is only two months, after all. It doesn’t seem to happen every year. But a weakened Polar Vortex is one of the predicted effects of climate change.


Kennedy, Caitlyn. 1/18/14. “Wobbly Polar Vortex Triggers Extreme Cold Air Outbreak.” ClimateWatch, National Oceanographic and Atmospheric Administration. http:// http://www.climate.gov/news-features/event-tracker/wobbly-polar-vortex-triggers-extreme-cold-air- outbreak.

M. O. Jeffries, J. Richter-Menge, and J. E. Overland, Eds., 2014: Arctic Report Card 2014, http:// http://www.arctic.noaa.gov/reportcard.

Baby, It’s Cold Outside!

Man, it was cold in early January! What’s with the temperature? On January 3, 2015, the temperature hit 3°F with a windchill of -8 in St. Louis. In Kansas City, it was 3°F with a windchill of -11. In Springfield, MO, it was 2°F with a windchill of -14. Meanwhile, in Chicago it was -14°F with a windchill of -27. It was even worse last year: in January 2014, the temperature in St. Louis hit -8, while in Kansas City and Springfield it hit -11 and -10°F.

Why is it so cold? Isn’t there this thing called global warming going on?

MO & USA Avg TempFirst, it is not as cold as we all may think. There may have been days of bitter cold, but there were also days of unusual warmth: for instance, in St. Louis, Kansas City and Springfield the temperature hit 60, 57, and 62°F, respectively, in January 2014. The same thing may happen in 2015 before January is over.

For Missouri as a whole, during January 2014, the average temperature was 25.9°F, only 3.9° colder than average, ranking it as the 22nd coldest January in the 120 years since record keeping began (see first chart at right). For comparison, the coldest January in Missouri averaged 13.9°F, 12° colder. For the United States as a whole, January 2014 was slightly warmer than average, at 30.54°F, the 55th warmest on record.

(Click on chart for larger view.)

World Jan Temp AnomalyFor the entire world, the average temperature for January 2014 was 0.64°C warmer than the long-term average, making 2014 the 5th warmest January on record (see second chart on right). Unfortunately, the Climate at a Glance data portal does not provide actual global temperature time series, only anomaly time series.





MO Hi Lo Chart 2The third chart at left shows what is really happening in Missouri. The red line shows the average temperature for January from 1885 through 2014. The dashed red line shows the trend over that time period. Overall, the average temperature in Missouri during January does not seem to be changing much.

The blue line in the chart shows the difference between the highest temperature and the lowest temperature during January. This is a measure of how variable our temperature is from day-to-day. The dashed blue line shows the trend. Overall, the difference between the high and low is decreasing slightly, but that disguises what’s really happening. During the first half of the 20th Century, there was relatively little variation between years, the highest and lowest temperatures during January didn’t differ by too much. But since the 1960s, the peaks and valleys of the blue line have spread out, meaning that some years there is less than usual variation, some years there is more than usual. Some years January is pretty “all-the-same,” and other years it is “all over the place.”

What does this mean? I don’t know. It would be a great topic for a research paper. I do know that there is an explanation for the “all over the place” years, and that will be the subject of the next post.


Source for January 2014 and January 2015 high and low temperatures in St. Louis, Kansas City, and Springfield, MO: The NOW/data database published by the National Atmospheric and Oceanographic Administration. To access the NOAA Local Forecast Office for each city, google “weather [city name]. Select the option with the URL that begins “www.crh.noaa…” On the webpage of the forecast office, in the column on the left, select “climate:local.” On the Local Climate webpage, select the “NOWdata” tab.Use the query portal to define your search. I searched for the St. Louis, Kansas City, and Springfield Areas, Daily Data for A Month, and 2014-01.

Source for Missouri and USA data: Climate At A Glance data portal, National Atmospheric and Oceanographic Administration. http://www.ncdc.noaa.gov/cag.

Missouri Tornados Up by 70% in 2013

2001-2010-stateavgtornadoesIn 2013 the number of tornadoes in Missouri increased by 70%, and the number of severe tornadoes tripled. It sounds dramatic, but it may be just part of the normal variability involving these terrible storms. I published my initial analysis of tornadoes nationally and in Missouri a year ago with data from 1950-2012. This post updates the information with data from 2013. Look here for my first post, which contains background information about tornadoes.

Missouri has a significant history with tornadoes. Over the last 10 year, Texas led the nation in the average number of tornadoes per year (142), with Kansas second (116), and Missouri third (61). The first map at right shows the data.

(Click on map for larger view.)

1991-2010-tornadoes-per10k-perstateTexas, Kansas, and Missouri are geographically large states, however. The second map at right shows the average number of tornadoes per 10 sq.km. of land area for each state for 1991-2010. Kansas is first ( it was second in the data I looked at last year). Florida is second (it was first last year). Some other states surprisingly high on this list include Maryland and South Carolina.


Missouri is also one of only two states with 8 or more tornado deaths per year over the last 10 years. The third map at right shows the data.

2001-2010-stateavgfatalsTennessee leads the nation in this sad statistic with 10, Missouri is second with 8, and the states tied for third have half as many as we do. Missouri has been hit by 3 of the 10 deadliest tornadoes in history. The damage caused by a tornado depends not only on the size of the tornado, but also whether it hits a populated area, whether it hits when people are awake and able to take shelter, and whether buildings are built to withstand the storms. We don’t have statewide building codes in Missouri, consequently there are many buildings that will not withstand a tornado and that have no place of refuge.

The nation had only one EF5 tornado in 2013, the tornado that devastated Moore, Oklahoma, a suburb of Oklahoma City. Initial reports overestimated the number of fatalities, with final estimates putting the number of deaths at 24. This compares favorably to the Joplin tornado, which killed 158. Oklahoma has a state building code.

Missouri’s most severe tornadoes in 2013 were 3 EF3 tornadoes. Two of them hit May 31 and tracked across the St. Louis metropolitan region, causing 2 injuries. The other hit northwest of Sikeston in Southeast Missouri, and tracked eastward through farmland.


For the Moore, Oklahoma tornado: I have been unable to find an official casualty count from a government source. Several news sources seem to agree that the count was 24, the number of names on the list of casualties published by the coroner’s office, with many more injured. For a general article on this tornado, see “2013 Moore Tornado,” Wikipedia, viewed 6/27/2014 at http://en.wikipedia.org/wiki/2013_Moore_tornado.

For the Joplin, Missouri tornado, a general article is available at: “2011 Joplin Tornado,” Wikipedia, last viewed 6/27/2014.

For the Harvester and South Roxanna tornadoes of 2013: National Weather Service Weather Forecast Office, St. Louis, MO. Severe Thunderstorms Produce Straight Line Wind Damage and Nine Tornadoes. May 31 2013. Viewed 6/27/2014 at http://www.crh.noaa.gov/lsx/?n=05_31_2013.

Does St. Louis Have a Tornado Alley?

“Does [the St. Louis] metro area have its own tornado alley?” asks a headline in the St. Louis Post-Dispatch? (article by Susan Weich, 7/6/14) The accompanying story notes that the metro area has experienced an increase in tornadoes since 2010, with 6 of them following similar paths through St. Charles and north St. Louis County.

As the story goes on, it becomes clear that it is too early to tell. The meteorologist interviewed, Greg Carbin of the Storm Prediction Center in Norman OK, explains that the year-to-year variability in these storms makes it premature to declare a trend.

The story also notes that the metro area has sprawled, making it a much bigger target for tornadoes to hit. (I’ve published several posts on sprawl – for the lead article in the series, see here.) Advanced radar technology peers into storms and finds tornadoes that used to go unnoticed. And people with cell phones report tornadoes from places where there once was no communication – and they even include pictures!

One hundred years ago, if a tornado touched down in O’Fallon or even Maryland Heights, it might have gone unnoticed. If a farmer saw it, he might have had no way to tell anybody else. Today, it might tear up a mall, get photographed by dozens of people, and have its path tracked in intricate detail by doppler radar.

So the answer is maybe, but it’s too soon to tell. Tornadoes might have a tendency to track through a certain part of the metro area, but it might also just be an unlucky streak for the people who live there.

I noted all these factors in my original series on tornadoes in Missouri last year (for the lead post, see here.) I’ll post an update with tornado information through the end of 2013 soon. And more on sprawl is coming soon, too.


Weich, Susan. 7/6/14. “Does the metro area have its own tornado alley?” St. Louis Post-Dispatch. Accessed online 7/6/14 at http://www.stltoday.com/news/local/stcharles/does-metro-area-have-its-own-tornado-alley/article_4bd90b14-c7be-560d-ad8c-c66956c1d6c6.html.

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