Explosives trigger three avalanches

The Daily Inter Lake

A blast of snow cascades over Shed No. 8 on the Burlington Northern Santa Fe railroad tracks near Essex on Saturday during avalanche-control operations in Glacier National Park. The snow slide was triggered by a 9-pound explosives charge dropped from a helicopter.

An effort to reduce the avalanche hazard in the Middle Fork drainage by tossing explosive charges from a helicopter yielded one medium-size avalanche and a couple of smaller ones on Saturday.

Burlington Northern Santa Fe Railroad, which runs numerous trains through the corridor every day, organized the assault after more than a foot of new snow fell in the area on Thursday night and Friday morning.

Glacier National Park spokeswoman Melissa Wilson said the company used nine 9-pound explosive charges and one 4-pound charge to bring down the slides in the Essex area.

"They dropped the charges in four different areas," Wilson said. "Three charges were dropped above Shed 8. That brought down a Class 3 avalanche that ran to the top of the shed, with a small amount crossing over."

Two small, Class 1 avalanches were started near "1163," the railroad's designation for a specific section of track. Other charges dropped above "Infinity" and Shed 7 failed to propagate any snow slides.

Several different methods have been used to describe and compare avalanches. One system rates them on scale of 1 to 5, like river rapids, with 5 being the largest possible slide.

A Class 3 avalanche, according to a British Columbia Ministry of Forests Web site, "could bury a car, destroy a small building or break a few trees." It typically contains about 1,000 tons of snow and could slide as much as a kilometer.

A Class 1 avalanche is "relatively harmless to people," with 10 tons of snow and a 10-meter slide.

Glacier National Park issued Burlington Northern an emergency, three-day permit for the avalanche control activity, which took place along the park's southern boundary.

The railroad "made the determination regarding the number of charges to use and where to use them," Wilson said. "We just monitored compliance [with the permit]. We also had a couple of people on the ground who closed the area and made sure there weren't any people present."

A three-mile section of U.S. 2 was closed for about two hours Saturday while the avalanche-control project was in operation.

In January 2004, two large slides in John Stevens Canyon, on the west side of Marias Pass, first blocked and then hit an empty, 119-car freight train. A third avalanche almost hit a cleanup crew and a fourth hit a truck traveling on U.S. 2.

The slides backed up rail traffic for 70 miles on both sides of the Continental Divide for 29 hours.