By Laura Zuckerman
March 3 (Reuters) - A woman buried alive with her husband by an avalanche that roared down a mountainside and swallowed their house in Missoula, Montana, late last week has died of her injuries, police said on Monday.
Michel Colville, 68, a textile artist, and her husband, Fred Allendorf, 66, a professor emeritus at the nearby University of Montana campus, were trapped and missing in the snow for hours before they were rescued on Friday evening.
An 8-year-old boy buried in the snow also was pulled to safety from a nearby yard about 90 minutes after the avalanche struck.
Colville died on Sunday night, Missoula police Sergeant Travis Welsh said, but there was no information available about the nature or extent of her injuries.
Allendorf, initially listed in critical condition, has since been upgraded to serious condition at St. Patrick Hospital, while the boy, who was not publicly identified, was listed in fair condition.
The avalanche swept down the side of Mount Jumbo during a blizzard at an estimated speed of 120 miles per hour (190 km per hour) and slammed into a neighborhood northeast of downtown, engulfing the two-story house where Colville and Allendorf lived.
The slide may have been inadvertently unleashed by a snowboarder, or others engaged in recreational activity, in an area of the mountain placed off-limits in winter to provide range for foraging elk, authorities said.
Welsh said investigators had interviewed several individuals who were in the vicinity where the avalanche appeared to have originated, but no arrests have been made and no charges were pending.
Police are likely to consult with a local prosecutor to decide whether to press ahead with a criminal investigation in the case, a gray area because of the extreme rarity of an avalanche within city limits, he said.
"We've never had an avalanche in town that I'm aware of, so we really don't know where this investigation will take us," Welsh said.
Welsh said the mountain is posted with signs warning of the closure and that violators could be cited for criminal trespass, a misdemeanor.
Almost all U.S. avalanches that affect people strike in the backcountry of the mountainous West and are triggered by snowmobilers, skiers and snowboarders seeking fresh powder, according to federal avalanche experts.
Colville's death brings to 18 the number of people who have died in avalanches in Western states so far this season, twice the tally for this time last year, federal figures show.
Government specialists say the rise in killer avalanches stems in part from unusually dense, wet snow that has blanketed the mountain West in recent months after an extended dry spell weakened a base layer of snow laid earlier in the season. (Reporting by Laura Zuckerman; Editing by Steve Gorman and Lisa Shumaker)