Weird weather: heat, twisters, 250K tons of snow

[March 17, 2012]  WASHINGTON (AP) -- America's weather is stuck on extreme.

Nearly 11 feet of snow has fallen on Anchorage, Alaska, this winter. That's almost a record, and it's forcing the city to haul away at least 250,000 tons of snow. Yet not much snow has dropped on the Lower 48 this year.

The first three months of 2012 have seen twice the normal number of tornadoes. And 36 states set daily high temperature records Thursday. So far this month, the U.S. has set 1,757 daily high temperature records. That's similar to the number during last summer's heat wave, said Jake Crouch, a climate scientist for the National Oceanic and Atmospheric Administration.

Six rare, but not unprecedented, March tornadoes struck Thursday in Michigan, which also set 26 heat records. Temperatures were in the 80s in some parts of the state.

Nationwide, there have been 132 tornadoes confirmed in January and February, with preliminary reports of more than 150 already in March.

Two different weather phenomena -- La Nina and its northern cousin the Arctic Oscillation -- shift storm and temperature patterns through the world, meteorologists say. Scientists say you cannot link a single weather event to global warming.

However, climate scientist Andrew Weaver of the University of Victoria says: "When you start to see the extreme events become more common, that's when you can say that it is a consequence of global warming."

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Online:

NOAA list of daily high temperature records set or broken Thursday: http://1.usa.gov/A1823b

NOAA tornado statistics so far:
http://1.usa.gov/wOrOsb

[Associated Press; By SETH BORENSTEIN]

Rachel D'Oro contributed to this report from Anchorage.

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