New England was plastered with unexpected wet snow up to 20 inches deep yesterday, the earliest on record for some places, and temperatures skidded to record lows as far south as the Gulf of Mexico.

The storm knocked out power to about 900,000 customers in the Northeast and stranded tourists who had hoped to see fall foliage.

"It's the last thing we expected. The last we heard, we were only supposed to get rain," said Louis Keezing of Northeast Utilities in Connecticut, which had about 85,000 customers without power.

Connecticut Gov. William A. O'Neill (D) ordered open the Civil Preparedness Emergency Operations Center in Hartford to coordinate public safety efforts.

States of emergency were declared in communities throughout Massachusetts' Berkshire County, including Pittsfield, North Adams and Williamstown, where the civil defense and all off-duty police and firefighters were called in.

Several highways were closed, including about 70 miles of the Massachusetts Turnpike, police reported.

The snow was caused by a cold pocket at an altitude of about 20,000 feet that moved in from Canada and mixed with a low pressure system carrying precipitation from the east, said meteorologist Mel Goldstein of the Weather Center at Western Connecticut State University.