Hundreds of thousands of homes and businesses sat cold and dark across the Northeast on Saturday as utility crews backed by National Guardsmen hacked through the wreckage of trees brought down by a vast ice storm.Utilities cautioned that it could be days before all power is restored, or even weeks in some places."The first day it was cool, now it's old already," said Pat Belina of Watertown, N.Y., who said she and her entire family were sleeping in one bed to keep warm at night.President Clinton declared a federal state of emergency Saturday for a five-county area of northern New York state, where Gov. George Pataki asked the federal government for blankets, food, drinking water and a truckload of diapers.Local states of emergency were in effect in parts of Vermont, New Hampshire and Maine.Last week's huge storm system caused floods across the South and spread thick ice across the Northeast and the eastern third of Canada, where 11 deaths had been blamed on the storm. Seven deaths were counted in Tennessee flooding plus two in North Carolina.In Maine, Central Maine Power Co. said an estimated 229,000 homes and businesses were still without power Saturday evening and Bangor Hydro Electric Co. said it couldn't guess. "We've stopped trying to count," said Bangor Hydro spokesman Bill Cohen.New Hampshire utilities still had about 40,000 homes and businesses without electricity and Vermont had some 9,000 blacked out. New York utilities did not have figures for homes and businesses but estimated the blackouts affected half a million people.Sunshine and warming temperatures both helped and hurt on Saturday. Ice coating trees in layers up to 2 inches thick began to melt and fell off in glittering chunks that crashed to the ground and endangered utility crews.At Gilford, N.H., resident Carolyn Beckdorff said she was grateful for the protection of a ski helmet as she cleared fallen limbs from her yard.The melting caused flooding in parts of upstate New York, and hundreds of families had been evacuated along the Hudson and Mohawk rivers.The weight of the ice also took down a 300-foot radio station tower Saturday at Laconia, N.H. No one was injured."It was completely coated with an inch or inch and half of ice," said Jim Kenton of WLNH radio.A force of 120 National Guard Humvees rolled across the upstate New York countryside around Plattsburgh on Saturday to clear paths for ambulances and food trucks. The New York National Guard also had sent 1,500 soldiers out to help.Plattsburgh was strained by the demands of people fleeing outlying areas in search of warmth and shelter."At least this place is warm, and we don't have to worry about getting sick now," Grace Fader said Saturday at a Plattsburgh school where she and 149 others spent the night.Residents of Wolfeboro, N.H., were told Saturday that some homes might stay dark for seven to 10 days. Police Chief Stanley Stevens appealed for volunteers to help clear debris.The lack of power demanded inventiveness.Some New Hampshire post offices stayed open with candles, lanterns and cars "parked to point their headlight strategically through windows to where people are working," said District Manager Winifred Groux.