NEW YORK, Dec. 12 (Xinhua) -- Fueled by several lake-effect snow events, snow amounts have generally been two to five times the season-to-date normal for the Great Lakes, but the United States in general has had just 68 percent of its normal snowfall to date as of Wednesday, reported The Washington Post on Thursday.
"While snow has fallen in parts of the southern Rockies, Northwest and high elevations of the Northeast, this season ranks as the 13th least snowy to date since 2008, when national snowfall records began," noted the report.
The Great Lakes have been the snowy exception, and more is coming from Thursday into Friday, leading to dangerous travel conditions along Interstates 90 and 81 in New York with two to three feet of snow expected to accumulate, according to the report.
The reason for the almost nonstop snow lies in cold air blowing over record warm water -- all of the Great Lakes except Superior are experiencing their warmest year on record, as of early December. For lake-effect snow to occur, there needs to be a temperature difference of at least 23 degrees Fahrenheit between the lake and the air about a mile above the ground, it said.
This extreme difference can lead to more atmospheric instability, the potential for thundersnow, heavier snowfall rates and even waterspouts over the Great Lakes, it added.
