The icy weather gripping Sonoma County claimed its first victim Saturday morning when a Santa Rosa woman lost control of her pickup on Highway 101 in Healdsburg and plowed into a group of trees.

The crash was one of numerous accidents around Sonoma and Mendocino counties overnight and early Saturday morning caused by a dangerous combination of overnight rain and frigid morning temperatures.

Overnight temperatures, which warmed slightly Saturday morning after a record low Friday morning, are expected to again plunge to the low 20s now that the rain has passed, meteorologists said.

The 52-year-old woman was driving a Ford Ranger pickup about 7:49 a.m. when she crossed over the Westside Road overpass, spun out on what was likely an icy patch of road, and crashed, CHP Officer Nenad Gorenec said.

The woman was conscious as rescuers cut her out of the crumpled vehicle, but after she was taken by ambulance to Santa Rosa Memorial Hospital she was pronounced dead, Gorenec said.

Her identity was being withheld until her family could be notified.

The investigation into the accident is still ongoing, but it seems clear the weather and road conditions contributed to the crash, Gorenec said.

"At this point we think it had something to do with her spinning out of control," Gorenec said.

After the driver left the road, the pickup crashed into one tree with such force that it uprooted it before careening into two other trees, Gorenec said.

Police and fire departments around the area reported numerous spin outs and accidents due to early morning icy conditions. Even after the sun warmed the air temperature above 40 there were still plenty of shady areas where icy conditions persisted throughout the morning.

There were three or four accidents attributable to icy conditions on Mark West Creek Road alone. None of the accidents on the two-lane road, which winds up into the hills east of Larkfield, involved significant injuries, Gorenec said.

CHP dispatchers in Mendocino also reported several accidents due to icy conditions but no fatalities.

Most were in a residential area north of Willits known as Brooktrails, said Jim Horton, a captain with Cal Fire.

"There were a bunch of cars sliding off the road up there," Horton said.

Other areas where snowfall or icy roads caused problems were Redwood Valley and the Highway 162 corridor up toward Covelo, Horton said.

After record low temperature of 22 degrees Friday in Santa Rosa a slightly warmer front moved through dropping rain on the low-lying region overnight and snow to the higher elevations. The peak of Mount Saint Helena was covered with snow Saturday morning as were the hills around the Geysers.

Colder, drier air swept in behind the front and temperatures fell just below freezing in Santa Rosa, to 31 degrees, during the early morning hours, said Carl Erickson, a senior meteorologist at AccuWeather.

While temperatures will remain in record cold territory for the next couple days, there is no more precipitation on the way, Erickson said.

It's expected to drop back down into the low 20s overnight and do the same Sunday, he said. Only gradually will it warm up later in the week, reaching overnight lows in the 30s by Wednesday, he said.

The cold temperatures and falling limbs caused by the storm contributed to 4,147 customers losing power around Sonoma County. The two largest failures were in Petaluma along Adobe Road, where 1,215 customers were without power, and Bennett Valley, where 2,709 customers were affected around 11:30 a.m. PG&E spokeswoman Jana Morris said.

By early evening power had been restored to all but two customers, she said.

You can reach Staff Writer Kevin McCallum at 521-5207 or kevin.mccallum@pressdemocrat.com. On Twitter @citybeater.