Freezing rain that iced Long Island roads led to multiple crashes Tuesday and forecasters warned that even more treacherous conditions could face commuters this morning.

Between a half and three-quarters of an inch of solid ice accumulation could hit areas of Suffolk and Nassau counties, according to the National Weather Service, which issued an ice storm warning for Long Island until 9 a.m. The freezing rain advisory is no longer in effect.

Travel conditions will be "extremely dangerous through early this morning," the service said. Temperatures will slowly climb back toward freezing by daybreak. 

Hundreds of schools on Long Island have issued 2-hour delayed starts or have closed. 

Snapped tree branches and downed power lines are also possibilities. The Long Island Power Authority said it would have an increased number of repair crews on standby. As of 6:19 a.m., 5,273 outages were reported in Nassau (2,727 in Hempstead, 2,517 in North Hempstead) and 436 in Suffolk.

"It's even more likely when we already have snow or ice accumulated," National Weather Service meteorologist John Murray said of tree limb or power line collapses.

As of Tuesday night, certain iced-over locations had become accident magnets.

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Dix Hills Assistant Fire Department Chief Tom Magno said at 9:30 p.m. there had been six separate accidents since 8 p.m. on the Northern State Parkway west of Deer Park Ave.

"It's terrible," Magno said. "The state's stretched so thin that we've been waiting here and they can't seem to get a sector car here."

No one has been hurt, but there is a bad stretch of ice at that location and cars are skidding out into the wall or into another car that has already crashed, Magno said. State Police said they saw similar accidents on both the Northern and Southern parkways.

Meanwhile, the Suffolk Sheriff's office said there were 27 wrecks on its roadways between 1 and 6 p.m.

The state Department of Transportation had extra workers out overnight pounding roads with salt.

"People need to be taking it good and slow," said DOT spokeswoman Eileen Peters.

The Long Island Rail Road also is bracing for problems. "Wintry icy conditions" caused the LIRR to switch over to a weekend schedule with reduced service.

"If we get a significant ice storm, or we just get a significant buildup of ice on the third rail, that could be as bad as a 14-inch snowstorm," he said.

The LIRR has fitted trains with a "record" 110 ice scraper shoes. The abrasive steel shoes scrape ice from the third rail as trains travel.

- With Alfonso Castillo and Bill Mason