Jetstream Strikes Again in Siberia : Heatwave, Flood, Now Torrential Flooding
August 20, 2013
The summer of 2012 was the most severe wildfire season Russia had faced in a decade. 2013 might be headed in the same direction after an unusual heat wave brought a surge of fire activity in northern Siberia in July.
A persistent high-pressure weather pattern in the Russian Arctic—a blocking high—contributed to the heat wave, which saw temperatures reach 32° Celsius (90° Fahrenheit) in the northern city of Norilsk. For comparison, daily July highs in Norilsk average 16° Celsius (61° Fahrenheit).
Blocking highs are so named because they block the jet stream from moving rain-bearing weather systems along their normal west-to-east path; this leads to “stuck” weather patterns with long periods of stable air and exceptional heat.
The map above shows land surface temperature anomalies for July 20–27, 2013. Rather than depicting absolute temperatures, the map shows how much the temperatures for that week differed from the long-term average for the area. The measurements were collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite. Shades of red indicate temperatures that were warmer than average; blues are below average. Oceans, lakes, and areas with insufficient data (usually because of persistent clouds) appear in gray.
The extraordinary and perhaps unprecedented heat wave continues in the central arctic region of Russia. Some locations have now endured 10 consecutive days above 30°C (86°F). Wildfires are erupting in the taiga forests. Norilsk maximum daily temperatures have cooled down a little, but yesterday (July 23rd) it enjoyed its warmest night so far with a low of 20.2°C (68.4°F).
Norilsk, with a population of 175,000, is located at 69° 20’N and 88° 6’E and is the most northerly city in the world with a population over 100,000.
The worst flooding in more than a century is ravaging Russia’s Far East, displacing thousands near the Amur River, which forms the border with northeastern China.
Russian authorities say 17,000 people had been evacuated by Saturday, and warned that figure could reach 100,000 in the coming days.
China’s official Xinhua news agency said Friday the flooding had killed 11 people and displaced more than 140,000 others on its side of the river, known in China as the Heilongjiang. It also said floodwaters had destroyed more than 2,500 homes, halted passenger rail service and inundated at least 1.4 million hectares
Floods that have hit Russia’s Far East cover an area of more than 2,000 kilometers by 500 kilometers, a senior Emergency Situations Ministry official said on Monday.
“It is a unique situation in the sense that it has spread over more than 2,000 kilometers if one looks from west to east, while its depth or width is more than 500 kilometers,” Vladimir Stepanov, head of the National Crisis Management Center of the Emergency Ministry, told a news conference in Moscow.
“There are hundreds of towns and villages and hundreds of thousands of people in the zone of the [rescue] operation,” he said, adding that most of the water causing the floods “is coming from China.”
A Song of Flood and Fire
As of late July, heavy rainfall had emerged in a dense band along eastern Russia and bordering north China. This band of dense and heavy moisture rose north over an ocean heat dome that was setting off very dangerous high temperatures over the region of Southeast China even as it was baking a large region of ocean, heating a vast expanse of the surface waters to above 30 degrees Celsius. The added moisture and heat content provided fuel for low pressure systems skirting the high.
By early August, major flooding had begun to occur in this eastern region as very heavy storms sprang up over this large area.
We can see the development of this massive storm system starting on August 4th in the image below:
In the above image, we are looking down on the Earth from a shot taken above the North Pole. The region we are looking at is Siberian Russia and Yakutia which dominates the central section of the image. Toward the lower left are the Laptev and East Siberian sections of the Arctic Ocean. Toward the central and upper left is Eastern Russia (Kamchatka), Mongolia, and extreme north China. In the upper right corner is central Asia.
Note the very dense region of clouds and rain pulsing up from the Pacific Ocean and overlaying Kamchatka and southern Yakutia. The storm at this point is vast and its cloud coverage immense. But it is just getting started.
By August 7, the storms had sagged toward the south, drifting slowly eastward along the monsoonal flow. Occasional pulses of moisture rose northward from the Pacific to refresh and intensify this storm and cloud flux. This action brought the Pacific and monsoonal storms in direct contact with a hungry low pressure system rising up out of Central Asia and moving from the southwest toward the northeast. By August 7 we can begin to see this storm system entraining the massive volume of moisture associated with the Pacific storm pulse and monsoonal flows.
The storm was emerging over a region of Yakutia that had experienced a massive and terrifying explosion of very energetic wildfires. The air was heavily laden with particles of dense smoke from a great burning that had intensified since late July. There the moisture erupted into a powerful deluge that by August 11th had broken flood records set as far back as 1896. By that time, more than 20,000 personnel had been mobilized to help deal with the floods as hundreds of homes and scores of roadways were inundated.
As of August 11, we see a massive and fully formed storm complex directly over Yakutia. The storm has now fully entrained the dense smoke cover belched out by the hundreds of fires, some of which were still burning throughout the region. It was also still drawing in moisture from the Pacific storms and monsoonal flow over south Russia, Mongolia and northern China. A second arm of the storm stretched northward linking the storm with the Arctic. With a strong south and north linkage, the storm had accessed energy to maintain strength and intensity for an extended period.
The large storm system continued to churn through Yakutia and by today, August 14th, a massive region covering 1 million square kilometers was inundated by floodwater. What we see in the satellite shot for today are not one, not two, not three, but four rivers of moisture linking the major storm system that has inundated Yakutia.
The first river of moisture is a continuation of the Pacific flow rising up along the southeast Russian coast, the second is the monsoonal flow moving from west to east to combine with this Pacific flow. A third flow feeds into the storm from Europe as it rides along parallel and to the north of the more southerly monsoonal flow. A final river of moisture rides up the from the storm, linking it to the Arctic and likely sharing energy and instability with that cold and dynamic region.
With a second low developing to the west of the first and moving along in its shadow and with moisture continuing to feed into these storm systems from the monsoonal flow to the south, it appears that rainy conditions will persist for the already inundated Yakutia region over the next few days at least. And if this pattern continues as predicted, it may well come to rival the great Pakistani floods of 2010.