WINTER SPORTS -- Snow that piled up in Western mountains after snow-drought conditions in January has created hazards that have caused a spike in avalanche fatalities among skiers and snowmobilers.

The nine deaths from avalanches across the Western U.S. in the past 11 days have put a halt to what had been the least-deadly season for avalanches in 16 years.

An avalanche near Ketchum, Idaho, on Sunday buried four snowmobilers, killing an Idaho man whose wife survived being buried under the snow for about 90 minutes, officials in Blaine County said.  

Two Wisconsin men were killed Saturday in a Colorado avalanche while backcountry skiing.

Five people were caught in avalanches over the weekend in Montana.  

• A 35-year-old woman suffered a broken leg Sunday after she was caught in a snow slide while back-country skiing near Big Sky in southwestern Montana. Gallatin County officials said she ended up partially buried and pinned against a tree.  
• On Saturday, a snowmobiler triggered an avalanche near Whitefish Mountain Resort that partially buried four people. The Flathead Avalanche Center said all four made it out of the area safely.  

On Feb. 11, an avalanche in the Wallowa Mountains of eastern Oregon killed two backcountry skiers and seriously injured two others.

For most of the winter, primarily because of the dramatic lack of snow in the Western mountains, only six people had been killed in avalanches, according to data from the National Avalanche Center in Bozeman. This was the lowest number through the first week of February since at least the 1998-99 winter season.

However, with the nine deaths in the past week or so, the winter's total is now 15, which is about average.

"A lot of snow in a little amount of time, you get avalanches," said National Weather Service meteorologist Chris Burke in Seattle.

On average, about 28 people a year die in avalanches in the U.S., according to Brian Lazar of the Colorado Avalanche Information Center. He said the deadliest seasons on record were 2007-08 and 2009-10, when 36 died in each of those winters.

When avalanche deaths were first tracked starting in the 1950s, an average of four people died each year in avalanches.

But the growth in winter backcountry recreation on skis, snowboards and snowmobiles has led more people into the potential hazards.

With more heavy snow falling in portions of the Inland Northwest -- notably the North Cascades -- backcountry travelers should be on high alert and willing to bail out for a backup plan.