January 31, 2008 (LPAC) -- It didn't look like global warming. A wall of snow 400 feet long and 30-feet deep fell from the slopes of the Snoqualmie Pass onto Interstate 90 earlier today, trapping several cars, but miraculously not injuring anyone. It was the second avalanche in two days on the stretch of highway through the Cascade Range about 30 miles east of Seattle.

The interstate had only been open for about five hours, after being closed Tuesday morning from an earlier avalanche onto the roadway in the same vicinity. Area residents cannot recall even a single such event in the past. As of Thursday afternoon, I-90 was closed through the Snoqualmie Pass. The National Weather Service issued a heavy snow warning for the west slope of the Cascades, North Cascades and the Olympic Mountains until Friday morning, with up to 3 more feet of snow expected.

Early in the week two storms converged, one from California and another from the Gulf of Alaska, dropping snow on mountain areas from Washington state to Arizona. These were followed Tuesday by a third storm over the northwest, while bitter cold air and blizzards descended on the northern plains, sending temperatures down 50 degrees in a few hours. Heavy snow stretched from the southeastern plains to Lake Erie. As of Thursday, the ice, snow and high winds were moving across the midwestern states, aimed to arrive in the northeast by early Friday.

For a view of the northern hemisphere snow and ice accumulation as of today, see: http://www.ssd.noaa.gov/PS/SNOW/