Posted Wednesday, March 21, 2001
Juneau Levels Guns at Mount Roberts
BLASTS: Heavy howitzer artillery shells are used to rid city of unexpected slides.
By Martha Bellisle
Anchorage Daily News
(Published March 21, 2001)
Juneau -- A steady rhythm of howitzer booms rattled windows and nerves in the capital on Tuesday, as a cannon crew shot from Douglas Island across Gastineau Channel to an active avalanche zone above a busy road south of downtown.
The shots started at about 10:30 a.m., just after the last Alaska Airlines jet flew out of the area and officials cleared the airspace. The aerial bombardment lasted for about an hour and a half.
The targets were large snowfields high on Mount Roberts, about 2.3 miles across the channel. That's a piece of cake for the 105mm howitzer, which has a range of 7 miles, said Mike Coffey, an engineer and safety officer for the state Department of Transportation.
Nineteen avalanche paths empty onto Thane Road, traveled daily by residents and twice daily by two school buses, according to Bill Glude, director of the Southeast Alaska Avalanche Center.
National experts consider Juneau one of the largest municipal avalanche hazard areas in the country because of the threat to Thane Road, as well as several large, active slide paths that lead down into busy neighborhoods.
Avalanches have hit, damaged or destroyed at least 72 buildings within a 10-mile radius of downtown Juneau in the past century.
Last winter, avalanches hit Thane Road a dozen times. The largest, triggered by highway crews blasting the Mount Roberts ridge, ripped down a power line and dumped a 30-foot-deep pile of snow that closed the road for almost two days.
Over the past 100 years, Thane slides have knocked over or buried vehicles, smashed water lines, crushed structures and killed or injured equipment operators clearing the road.
The power lines that run along Thane Road carry about 70 percent of the electricity used by the City and Borough of Juneau, adding incentive to keep the avalanche threat under control, Coffey said.
Since early Sunday, strong, frigid winds blasting out of interior Canada have dumped snow on the west face of Roberts, the lee side of the ridge.
On Monday, a small slide dumped several inches of snow and debris on Thane Road, said Karl Loveid, the crew's chief gunner. It let loose at about 9 a.m., prime time for the commuter and school bus traffic that travels between Juneau and a residential area at the end of the road.
No one was caught in that slide, and road crews had the road open quickly. But, it signaled avalanche danger.
"Thought we'd see if we could rattle a little more loose today," Loveid said. He coordinated the crew at its site just south of the town of Douglas.
"We usually shoot on a warming trend," added Coffey. "But with this severe wind, it's loading at the tops of the peaks."
Time to shoot high.
The department closed Thane Road, then with military precision the crew aimed the howitzer along predetermined coordinates -- they can shoot blind on stormy days -- loaded the 3-foot-long cartridges and BOOM!
Long seconds later a puff of black smoke appeared on the distant white ridge, and the crew waited for a fracture line to appear across the slope.
The team repeated the routine 19 times, but only got a few small slides to release. That seemed to disappoint Coffey. But, he said, "At least we know it's stable up there."
Reporter Martha Bellisle can be reached at ADN Article and 907-586-1531.