DENVER -- A potent winter storm quickly dumped up to two feet of snow in the Colorado mountains before moving into the populous Front Range on Thursday, knocking out power, closing highways, shutting down schools and canceling flights.

The storm arrived early Thursday morning but by noon, the snow had diminished in the metro area and the storm system was moving southeast.

Evening commuters saw clear skies and mostly clear roadways, which was dramatically different from the messy, sometimes treacherous morning commute.

Poor visibility caused by high winds and heavy, wet snow forced some drivers to slip and slide off the road.

Blizzardlike conditions were reported in the southern metro area -- Douglas County and southern suburbs -- and in the foothills.

The storm hit hardest in the mountains, foothills and the east. Snow totals vary across the Denver area, ranging from 4 to 7 inches on the northeast side of the metro area, with 1 to 2 feet in the southern and western suburbs. Click here for complete snow totals.

Highways Impacted

The westbound lanes of Interstate 70 were shut down between Golden and Silver Plume most of Thursday morning, due to adverse conditions. The eastbound lanes were closed between Silverthorne and Beaver Brook but reopened during the noon hour Thursday. Further east, near-zero visibility and icy roads prompted officials to close 150 miles of eastbound I-70 from Denver to Burlington, near the Kansas border. It reopened at 5 p.m.

Interstate 25 was also closed for several hours between north Colorado Springs and the Greenland exit, south of Castle Rock. It reopened just before 11 a.m., but Colorado Highway 83 remained closed between Franktown and Colorado Springs.

Northbound I-25 from North Academy Road in Colorado Springs to Casle Rock was the only stretch of highway to remain closed for the evening.

Click here to check updated highway closures from the Colorado Department of Transportation.

A rockslide was reported along I-70 at Silver Plume early Thursday morning and a snowplow driver's truck was struck by a large boulder. The rockslide forced the closure of the westbound lanes until the rocks could be cleared. The truck driver received minor injuries.

Schools, DIA Impacted

Many schools canceled classes or set late start times Thursday. Business, courthouses and voting centers were also shut down because of the bad weather.

Others schools closed due to power outages caused by heavy snow pulling tree limbs onto power lines. Hundreds of trees snapped because of the weight of wet snow.

Xcel Energy said that 45,000 customers were without power earlier Thursday in Thornton, Federal Heights and Northglenn areas. Power was restored there after a few hours. About 28,000 customers were without power in the rest of the metro area. A spokesman said most should have power restored by midnight.

Up to 100 flights were canceled Thursday at Denver International Airport, mostly on United Airlines, the airport's busiest carrier. United, Frontier and Southwest airlines also reported delays of up to an hour and 25 minutes.

"We expect it to be slow going through mid-afternoon," Southwest spokeswoman Paula Berg told the AP.

Flights leaving on Friday are expected to be full because of Thurday's cancellations and delays. To check flights in and out of DIA, visit www.flydenver.com.

Pena Boulevard, the main route to DIA, had gusty winds which caused visibility problems with blowing snow. Travelers were advised to use caution traveling to and front the airport so they can avoid "Pena Collidas." (ha ha.)

City and state road crews were out maintaining the roads for commuters. Michael Contreras with the Denver Department of Public Works said he had more than 60 trucks and crews working.

Colorado Department of Transportation officials said trucks statewide, including 100 in the Denver area, spread sand and deicer to keep traffic flowing for the morning commute, said CDOT spokesman Mark Aultman.

Avalanche Danger

Meanwhile, avalanche experts said recent storms have left a snowpack of up to 2 feet in the mountains and several avalanches have already been reported, including 10 in the past week on he east side of Ten Mile Range in Summit County.

"We've been finding a few things that are worth watching as the snowpack builds," said Colorado Avalanche Information Center forecaster Scott Toepfer. A recent snowfall did not bond well with the snow surface from a late-September storm, creating ripe conditions for avalanches.

The center usually begins issuing regular avalanche forecasts in November.

Red Cross Ready

Out east, Red Cross officials sent supplies to the plains' town of Byers in case predicted winds of up to 45 mph created whiteout conditions on the 150-mile flat stretch of Interstate 70 to the Kansas state line and forced the main east-west route's closure.

"After (Hurricane) Katrina, you think differently about everything," said Robert Thompson, spokesman for the Red Cross. "I think we all learned good lessons from that. Whether it really hits hard or whether it blows over, come on, this is Colorado. Who knows? But we're ready to go."

A trailer with cots, blankets, water, and snacks was sent to the Byers Fire Station, where the Red Cross set up shelter for travelers stranded by storms in March and November.

Stay with 7NEWS, TheDenverChannel.com and Comcast Digital Cable Channel 247 for the latest. Colorado's most trusted meteorologist, Mike Nelson, and the team of 24/7 Weather Center meteorologists, will keep you ahead of the storm.