Rain and warming temperatures are predicted for Friday, but not in time to prevent another nerve-testing morning commute.

Temperatures are expected to hit the 40s, which should begin thawing out Snohomish County and much of western Washington.

While parts of the Puget Sound region endured a rare ice storm Thursday, an unexpectedly heavy snowfall again swept across Everett. The skies were the color of lead well into the afternoon.

Highways and city streets continued to pass for skating rinks Thursday. The weather mayhem sent a state Department of Transportation worker to the hospital with broken bones, and it took hours to right a jackknifed semi-truck on I-5 near Lynnwood.

The icy conditions delayed flights at Sea-Tac International Airport, caused power outages and cemented the closure of schools, libraries, courtrooms and other government offices in many corners of the county.

Weather forecasters said warmer air was moving inland and temperatures were expected to moderate overnight.

The warming should bring some relief from compact snow and ice, but it will be a gradual melt.

“You could be seeing another frozen morning commute,” state Department of Transportation spokesman Travis Phelps said.

Phelps warned that the softening ice should not embolden drivers too much.

“That slush will grab your front tire and spin you around before you know what happens,” he said.

Dennis D’Amico, a National Weather Service meteorologist, said conditions should improve over the next few days. While flooding is not foreseen along local rivers, it could become an issue in some neighborhoods. Some parts of the Snohomish County are blanketed by more than a foot of snow.

“With all the melting snow comes the ponding problems with storm drains,” D’Amico said.

Washington State Patrol trooper Keith Leary said he would be hard-pressed to remember a time in the past few years when the weather created nastier road conditions in Snohomish County.

“It’s treacherous and dangerous, and I don’t use those words very often,” Leary said. “I had to pull those words out of the vault.”

The Transportation Department worker was injured while he was outside of his vehicle on I-405 just east of where the highway crosses I-5 near Lynnwood. Steven Cloud, 36, was helping the driver of a 2003 Ford Expedition that spun out of control and slammed into a concrete barrier. Another car rammed into the vehicle, which struck him.

Cloud was taken to Harborview Medical Center in Seattle. He was listed in satisfactory condition with several broken bones. The accident closed southbound I-405 for several hours.

The State Patrol said the accident likely was the result of driving too fast for conditions.

The jackknifed semi had been carrying a 42,000 pounds of oranges north on I-5 when it slipped off the roadway near the interchange with I-405 before daybreak on Thursday. The driver, 42, was not injured.

Thousands of homes lost electricity on Wednesday and Thursday as the weight of snow and ice toppled tree branches into power lines.

Outages spiked Wednesday night to about 10,000 homes, Snohomish County Public Utility District spokesman Mike Thorne said. That number sharply fell Thursday morning but rose again to about 11,500 homes in the afternoon as the continuing snowfall snapped more branches.

The outages were scattered around the county, PUD spokesman Mike Thorne said. That peaked around 10,000 homes Wednesday night.

Downed power lines caused at least two vehicle fires in east Monroe, Fire Marshal Mike Fitzgerald said. Meanwhile, a large tree toppled across Olympic Boulevard in Everett.

Between Tuesday and Thursday, firefighters in the Clearview area responded 18 calls for downed trees and wires, said Autumn Waite, spokeswoman for Snohomish County Fire District 7.

Frontier Communications crews worked to repair phone lines in Lake Stevens knocked down by fallen trees. About 2,500 customers in the Western Washington area lost phone service.

Many shops in downtown Everett were shuttered Thursday. Those that stayed open found few customers walking through their doors, except for those establishments specializing in coffee, hot soup and liquor.

“Coffee with Baileys,” said Amber Lang, describing what many customers coming into the Vintage Cafe seemed to be ordering.

She said business was surprisingly robust considering the weather.

“People were wanting coffee all day and all night,” she said.

That was certainly the case at Starbucks on Colby Avenue, where plenty of people wearing their warm, winter hats were nursing paper cups of coffee inside. One of the baristas made it to work on his bike and wondered how he’d make it home.

Nearby on Colby, two new business owners wondered if the snow was typical of Everett. Minh Tran and Ky Nguyen just moved to the area from Georgia to open up a Vietnamese restaurant. Just days after they opened, they found they had to shut their doors because of the weather, Tran said.

Gov. Chris Gregoire on Thursday declared a state of emergency.

She issued a proclamation that allows activation of the Washington National Guard and frees up state agencies to respond faster to storm-related requests from cities and counties.

Another provision aims to ensure milk and other dairy products get delivered without spoiling. It does so by waiving rules limiting the number of hours that drivers of trucks hauling intrastate bulk milk shipments from farms to dairy processing facilities and from dairies to processing facilities can work. The waiver expires Sunday.

Snohomish County offices were declared closed until 1 p.m. Thursday, although many workers didn’t get notice early enough and showed up to do their jobs in county offices.

Sheriff John Lovick said these are some of the worst road conditions he’s seen in years.

The county has been deploying 40 trucks clearing snow and ice from the streets.

In Everett, city crews plowed 457 miles and spread 200 yards of sand between 8 p.m. Wednesday and 8 a.m. Thursday.

Several school districts announced that they have canceled Friday classes. Those districts included Arlington, Edmonds, Everett, Index, Marysville, Mukilteo, Lake Stevens, Stanwood, Snohomish, Monroe, Granite Falls, Northshore and Sultan. Others were expected to make their plans known by daybreak.

Reporters Noah Haglund and Jerry Cornfield contributed to this story.