The Russian Heat Wave Bakes On

Events no one has ever seen before have arrived, and stayed:

The Great Russian Heat Wave of 2010 continues

One of the most remarkable weather events of my lifetime is unfolding this summer in Russia, where an unprecedented heat wave has brought another day of 102°F heat to the nation's capital. At 3:30 pm local time today, the mercury hit 39°C (102.2°F) at Moscow's Domodedovo Airport. Moscow had never recorded a temperature exceeding 100°F prior to this year, and today marks the second time the city has beaten the 100°F mark. The first time was on July 29, when the Moscow observatory recorded 100.8°C and Baltschug, another official downtown Moscow weather site, hit an astonishing 102.2°F (39.0°C). Prior to this year, the hottest temperature in Moscow's history was 37.2°C (99°F), set in August 1920. The Moscow Observatory has now matched or exceeded this 1920 all-time record five times in the past eleven days, including today. The 2010 average July temperature in Moscow was 7.8°C (14°F) above normal, smashing the previous record for hottest July, set in 1938 (5.3°C above normal.) July 2010 also set the record for most July days in excess of 30°C--twenty-two. The previous record was 13 such days, set in July 1972. The past 24 days in a row have exceeded 30°C in Moscow, and there is no relief in sight--the latest forecast for Moscow calls for high temperatures near 100°F (37.8°C) for the next seven days. It is stunning to me that the country whose famous winters stopped the armies of Napoleon and Hitler is experiencing day after day of heat near 100°F, with no end in sight.

Thousands of deaths, severe fires, and the threat of radioactive contamination

The extreme heat has led to thousands of premature deaths in Russia. According to Yevgenia Smirnova, an official from the Moscow registry office, "We recorded 14,340 deaths in Moscow in July, that is 4,824 deaths more than in July, 2009." Undoubtedly thousands of additional premature deaths have occurred in the rest of Russia as a result of the heat. The heat has also caused the worst drought conditions in European Russia in a half-century, prompting the Russian government to suspend wheat exports. The drought has caused extreme fire danger over most of European Russia (Figure 3), and fires in Russia have killed at least 50 people in the past week and leveled thousands of homes. The fires are the worst since 1972, when massive forest and peat bog fires burned an area of 100,000 square km and killed at 104 people in the Moscow region alone. Smoke from the current fires spans a region over 3,000 km (1,860 miles) from east to west, approximately the distance from San Francisco to Chicago. Dozens of flights were canceled at Moscow's airports today, thanks to visibilities of 300 meters in smoke. Also of concern is fires that have hit the Bryansk region of western Russia, which suffered radioactive contamination from the Chernobyl nuclear disaster in nearby Ukraine. There are fears that fires may burn through the contaminated area, releasing harmful radiation into the atmosphere.

...Why has Russia's heat wave been so long and intense?

Dr. Rob Carver has done a detailed analysis of the remarkable Russian heat wave in his latest post, The Great Russian Heat Wave of July 2010. A persistent jet stream pattern has set up over Europe, thanks to a phenomena known as blocking. A ridge of high pressure has remained anchored over Russia, and the hot and dry conditions have created helped intensify this ridge in a positive feedback loop. As a result, soil moisture in some portions of European Russia has dropped to levels one would expect only once every 500 years.