Summary: | Tim Woollings discusses the reasons behind the natural events such as the cold European winter of 2009-10, heatwave in Russia, and devastating floods in Pakistan. The jet streams are literally jets of fast-moving air that are strongest about 10km up in the atmosphere - around the level where airliners fly. Jet streams vary in strength from week to week. One of the most common variations in the North Atlantic jet stream is for the whole jet to shift to the north or the south. While the North Atlantic jet stream generally points roughly due east, straight across the Atlantic, it often meanders north and south. When waves on the ocean surface become too large they overturn and break, resulting in very turbulent motion. When Rossby waves break, the resulting weather situation is known as blocking.
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