Huge weather system hammered Alaska with an avalanche, wind – even thundersnow and rain

A massive weather system over Alaska generated a series of winter storms throughout the state and left Southcentral drivers coping with streets that were slow to be cleared of snow.

Amid heavy snow and whiteout conditions Monday in Fairbanks, a pickup and fuel truck collided on the Richardson Highway, sending multiple other vehicles into the ditch and closing the highway for hours.

Strong winds in Kodiak knocked down trees and knocked out power overnight for some residents.

A 100-foot-wide avalanche early Tuesday morning closed the Richardson Highway at Mile 195 near Summit Lake, according to Alaska Department of Transportation spokeswoman Meadow Bailey. Crews were working to clear the highway by midday.

And heavy snow, mixed in places with rain or freezing rain, piled up in Southcentral as plow trucks struggled to keep up and a surprise overnight burst brought more accumulation before the storm moved on.

Anchorage snow totals ranged from 11 inches on the Hillside to 7 1/2 inches at Ted Stevens Anchorage International Airport. Nine inches fell on the city's east side — 5 inches of it after 10 p.m., said Michael Kutz, a National Weather Service meteorologist.

Sutton in the Matanuska Valley registered 17 inches of snow, including freezing rain and sleet, Kutz said. Other parts of the Valley were reporting lower amounts.

The combination of this storm and the last left Anchorage and Mat-Su residents Tuesday morning contending with a sloppy drive to work or school, especially on uncleared side streets.

The problem stemmed from "back-to-back-to-back-to-back" snowfalls from four events in five days, as an Anchorage municipal street maintenance update Tuesday morning put it.

The state cleared the highest-priority Anchorage roads, such as the Glenn Highway, first and was moving to the next-level roads Tuesday, spokeswoman Shannon McCarthy said. That included much of the urban stretch of Northern Lights Boulevard.

McCarthy said she expected plowing to continue through at least Wednesday and couldn't say what the schedule was for Anchorage's sidewalks, which would be cleared after the streets are. DOT brought in additional sidewalk blower operators over the weekend, she said, but crews will need to haul snow to dumps around the city before those can start working.

Anchorage plow trucks trying to clear residential streets quickly ditched the usual tandem formation and went to single file as residents wondered when they'd get plowed out.

[Why isn't my street plowed? Here's what to know about snowplowing in Anchorage.]

In the Matanuska-Susitna Borough, the state cleared high-priority roads such as busy sections of the Parks and Glenn highways first, McCarthy said. Crews were turning to second-level priorities Tuesday such as the Palmer-Wasilla Highway.

State budget cuts three years ago limited plow operator positions and also cut into overtime, which is "how we deal with larger storms," McCarthy said. But the state authorized overtime for Mat-Su and Anchorage "because we knew this was going to be back-to-back storms and we needed to get on top of it," she said.

Borough contractors handling snow removal across 16 road-service areas scrambled to clear school bus routes, primary collectors and then secondary and subdivision roads.

"We're up to our necks in it now," said Terry Dolan, the borough's public works director.

All borough roads were plowed by Tuesday morning and contractors were clearing berms out of driveways if they measured more than 12 inches high on the homeowner's side, Dolan said.

The borough found it would cost twice as much to clear berms altogether and would probably raise taxes in some areas, he said. "Nobody likes berms but people hate taxes more."

The seemingly statewide weather system wasn't really one big storm, or even that unusual, forecasters say.

The weather driver was an upper-level trough maybe 1,400 miles long that stretched from the Gulf of Alaska to the Arctic Ocean, according to Kutz. Troughs are associated with low pressure that brings unstable weather.

Varying topography on the ground then generated differing storms across the state Monday.

Kodiak got hammered with winds forced by high pressure in Southwest Alaska through gaps in the Aleutian and Alaska ranges, according to meteorologist Bob Clay.

Gusts knocked trees into power lines, causing outages and also "significant damage" to areas of the Kodiak Electric Association system, according to an update Tuesday morning. Power was back on for most of the system, but pockets mainly in the Monashka Bay area and Chiniak remained dark.

"Due to the magnitude of the damage in some areas, power will probably not be fully restored until tomorrow," the utility wrote in a Facebook update. "We have additional support flying in from Anchorage to assist us in repairs, but it just takes time fix the number of issues that occurred."

In Southeast, low pressure over the northern Gulf of Alaska generated a strong onshore flow that brought wind, snow and then rain and freezing rain.

Near whiteout conditions and cold temperatures dominated the North Slope.

And yes, Homer had thundersnow near Diamond Ridge on the east side of town, Kutz said.

The infrequent phenomenon sounds more like a "whoompf" than a loud crack or boom, he said.

Snow lightning creates the thunder, Kutz said, but it's not white because of all the moisture in the air.

"I've seen 'em in green, orange and purple in my lifetime," he said.

Avalanche danger was moderate at all altitudes in the Turnagain Pass area of the Kenai Peninsula, according to the Chugach National Forest Avalanche Information Center.

"Expect loose snow sluffs in steep protected terrain. Additionally, old weak layers deeper in the pack may be triggered, creating a larger avalanche. Evaluate snow and terrain carefully," the center said.