Map in the video:
Tuesday, October 2, 2012
Thursday, March 1, 2012
The Volcano That Blasted This Winter
Most people don’t even know anything about Grímsvötn. It blew up in the middle of Iceland last May. Ash and chemicals roared 12 miles high into the air. Then everyone discovered that its ash was too high to mess with air travel to Europe and forgot about it. Unfortunately, the ash and chemicals are still lingering in the air, even if no one cares. They block out sunlight in parts of the Arctic. The air cools. Air pressures change.
What has happened is as simple as 1, 2, and 3.
- Winds really make a difference in winter. They can blow Arctic air deep into North America or away from the US.
- Air pressure determines where the winds blow. In the North Atlantic, the low pressure near Iceland (called the Icelandic low) steers the winds.
- The volcano in Iceland changed the air pressure over Iceland. The Icelandic low became very low.
The Icelandic Low is so strong that it has created a positive NAO. Source: NOAA
Even now, the NAO is shifting between neutral and positive. It sometimes allows cold air to hit the US, and then it zips it out into the Atlantic. The cold doesn’t stay very long.
It doesn’t mean that it doesn’t get cold. A huge storm from Siberia, “The Beast from the East”, has hit Europe. China has shivered with temperatures below normal since January. Two cold spells plunged down and killed people in India.
Still the cold winter has avoided most of the US. The blast of Grímsvötn, a volcano in Iceland, has warped the normal Arctic winds. In the process, it warmed the US. If you are seeing flowers in February, point to the volcano!
Posted by Steve and Izzy at 4:06 PM