The heat is really on

Record highs lead to meltdown in Glacier National Park

A prolonged heat wave is causing a rapid meltdown in Glacier National Park, triggering avalanches and causing some unexpected water problems on Going-to-the-Sun Road.

Several straight days of hot, sunny weather have settled over the park, and more of the same is in the forecast. Temperatures soared to 64 degrees Tuesday at Logan Pass, an area that typically is very winterlike in mid-May.

A high of 89 degrees Tuesday afternoon at West Glacier set a record, topping the previous record high of 81 degrees set in 1973.

Wednesday's weather offered a repeat performance with another record hot day for West Glacier, plus temperatures ranging from the mid-80s in the Flathead Valley to record mid-90s at Libby and Eureka. New temperature marks also were set at Hungry Horse Dam.

The snowpack at high elevations has retreated visibly this week, said Blase Reardon, a U.S. Geological Survey technician who does avalanche forecasting in Glacier Park.

"At upper elevations, the snowpack didn't really start melting until this heat wave," Reardon said. "Now you can see rocks and other features starting to emerge up high."

The resulting runoff led to a plugged culvert on the lower stretch of Sun Road in the Haystack Creek drainage, causing water to flow over the road. Crews worked to contain the flows and prevent erosion beneath the asphalt.

"We didn't expect it this time of year," said Shaun Bessinger, a road crew leader at the park. "Runoff doesn't usually come all of a sudden like it did the last few days due to warm temperatures."

Bessinger said he expected it would take two or three days to protect the road and unplug the culvert.

What's unusual about the weather, Reardon said, is that it has been prolonged.

"It's not a three-day thing," he said. "That's what we typically get - three days of sunny weather. It seems like this has parked right on top of us."

Temperatures aren't dropping at night, which would slow down the melt. At 1 a.m. Wednesday, the temperature at Logan Pass was 60 degrees.

Those overnight temperatures played a part in a large avalanche breaking loose on the southern slopes of Heaven's Peak. The Class 3 avalanche was "big enough to take your house and chew it up into small pieces," Reardon said, adding that the slide ran 4,000 vertical feet, coming to a stop about 1,200 feet from Sun Road in the Avalanche Creek area.

Plowing was suspended on Sun Road, partly because of the problems in the Haystack drainage but mostly because of increased avalanche danger. But the warm weather is expected to continue into next week, which should allow road clearing to continue.

"We're losing over an inch of water a day up high, so this snowpack is going to go fast," Reardon said. "It's not going to be gone in a week, but it's going to go."

Rapid runoffs in past years have caused flood problems in the park, particularly on Divide Creek near St. Mary. But that's not the case this year, said Pete Webster, the park's Triple Divide subdistrict ranger.

"Things are flowing, but it's nowhere near flood stage," he said, referring to Divide Creek.

Elsewhere in Northwest Montana, the National Weather Service issued a flood watch Wednesday for the Yaak River west of Libby. The river is expected to approach flood stage early this morning and may exceed flood stage by tonight.

The main Flathead River, along with the North and Middle Forks, are expected to approach flood stage on Friday.

The weather service predicts one more day of scorching heat. Highs today are forecast to reach 91 degrees in West Glacier and Kalispell. Temperatures should drop slightly on Friday, with highs in the low 80s.

Reporter Jim Mann may be reached at 758-4407 or by e-mail at jmann@dailyinterlake.com