Plan underway to use old quarry for staging for avalanche control

By Soren Wuerth

TNews Editor

A heliport and munitions depots filled with up to 20 tons of explosives are planned for construction at the foot of Orca Mountain, 0.8-mile from Old Girdwood, to improve avalanche control along Turnagain Arm.

In a presentation before Girdwood's Land Use Committee, Timothy Glassett, manager of DOT's avalanche program, said the Howitzer cannons the department currently uses are no longer viable. 

Technicians from Joint Base Elmendorf-Richardson no longer maintain the cannons, so DOT has to fly specialists up from Colorado. Meanwhile, the artillery program is getting more expensive, with the cost of ammunition going up "fivefold", Glassett said.

Seward Highway has one of the highest avalanche risks affecting traffic in the state. Avalanche experts use a complicated mathematical formula called an "Avalanche Hazard Index" to assess the amount of mitigation required for control. The Seward Highway along Turnagain Arm has an index one-and-a-half times greater than that of Thompson Pass, near Valdez.

An avalanche runs out to Turnagain Arm near Milepost 98 of the Seward Highway in this undated photo, (Photo courtesy of AKDOT)

Before a section of Seward Highway near Girdwood was moved to tidewater, it was the most dangerous highway in North America, Glassett said.

Glassett showed a video of a massive avalanche racing down the Peterson runout just south of Girdwood and across Turnagain Arm. There were audible gasps from the audience.

DOT's avalanche control division is trying to get funding for a newer method of control, Remote Avalanche Control Systems (RACS), which detonates explosives over a snowpack.

DOT, along with the Alaska Railroad and Chugach Electric—which also need avalanche control for their operations—are seeking permits for a heliport and six ammunition magazines at the old Virgin Creek gravel pit about a quarter mile south of the intersection of the Seward Highway and Alyeska Highway. The area is currently used as an informal mountain bike park. 

Responding to a question from an audience member, Glassett said Girdwood's current airport can't be used because explosives can't be flown over roads and homes. 

"This really is the ideal location for this type of operation," Glassett said. "Additionally, if Alyeska Resort would ever want to come into this... this would also be a location for them to sling up to their ridge if they ever built out RAC systems."