BLIZZARDS AND AVALANCHES

What is a blizzard?

According to the U.S. National Weather Service, a winter storm is considered a blizzard when wind speeds reach 35 miles (56 kilometers) per hour and there is poor visibility of less than one-quarter of a mile (400 meters). Snow does not need to be falling at the time, but blowing and drifting should occur with drifts exceeding 10 inches (25 centimeters) deep.

How bad was the Blizzard of 1888?

After a severe blizzard hit the High Plains of the United States in February 1888, causing the deaths of many people and farm animals, an even more destructive blizzard wreaked havoc on the East Coast from Maine to Chesapeake Bay from March 11 to 14. Several feet of snow fell all over the region, and in Saratoga Springs, New York, 52 inches (1.32 meters) of snow fell and there were drifts of up to 52 feet (16 meters) deep. Wind speeds ranged up to 70 miles (113 kilometers) per hour. By the time the storm was over, more than 400 people had lost their lives.

How destructive was the Blizzard of 1996?

The Blizzard of 1996 left a path of destruction from Georgia to Pennsylvania. Almost $600 million in insurance claims were filed and 187 people lost their lives. Two or more feet of snow covered Washington, D.C., West Virginia, New England, and New York City. In addition, about $700 million in flood damage was reported in Pennsylvania. All together, this one storm cost $3 billion.

What should you do if you are stranded in your car during a blizzard?

If you are far from any buildings or people who might help, rather than getting out of your car and wandering off, possibly getting lost or freezing to death, it is always

Do loud noises trigger avalanches?

The notion that making loud noises, such as shouting or clapping one's hands, near dangerous snow conditions will trigger an avalanche is an old myth. Actually, it would take a tremendous sound, such as a nearby sonic boom where an avalanche is about to occur anyway, for noise to make a difference. In 90 percent of cases, avalanches are precipitated by a person's or persons' weight, or the weight of a snowmobile or other machine, on top of unstable snow.

a better idea to remain in your vehicle. Hopefully, you will have a charged cell phone handy, but if not it is still better to remain in the car. After checking to make sure that the car's exhaust pipe is not blocked by any snow or ice (being wary of carbon monoxide poisoning), keep the car running for as long as possible to stay warm. Also, turn on your hazard lights, which may attract help, such as a police officer, while also warning snow plows not to come too close. During the winter months, it is a good idea to keep blankets, food, a spare tire, and a first aid kit in your car. Never drink alcohol to try and stay warm, but a thermos containing a hot beverage or soup would prove handy.

What happens to domesticated animals during blizzards?

Farm and range animals certainly suffer as much as people during blizzards. For example, in the Blizzard of 1886 that hit the central plains states of America, about 80 percent of livestock perished in the worst-affected areas of Texas, Oklahoma, Nebraska, and Kansas. In 1966, 100,000 head of livestock died in Nebraska, Minnesota, North Dakota, and South Dakota when a blizzard dumped 30 feet (9 meters) of snow, drifts of up to 30 feet (over 9 meters) accumulated, and winds gusted up to 100 miles (160 kilometers) per hour.

What causes avalanches?

The most dangerous conditions for an avalanche occur when a lot of snow has fallen and/or blowing wind has caused snow to accumulate within a short period of time (hours or a few days, versus weeks). A "dry slab" avalanche is the most hazardous. This is when a heavy slab of snow that has formed quickly is resting above another layer of snow that is weaker but formed over a longer period of time. Dry slab avalanches are usually set off by a person walking over the unstable layer. There are also "wet slab" avalanches, which, as one might guess, involve a layer of wet snow over a harder layer of snow.

Avalanches are most likely to occur on hills with inclines of 30 to 45 degrees, though wet snow can tumble down a hill with a grade of as little as 10 degrees, and dry snow regularly causes avalanches on hills with about 20 to 22 degree slopes. Avalanches happen abruptly, and once a slab has broken off, there is usually no escape for someone downhill. Traveling at 60 to 80 miles (95 to 130 kilometers) per hour, an avalanche will quickly bury everything in its path.

What is the most dangerous month for avalanches?

More avalanches occur during the month of February in the United States than any other month. Colorado, Alaska, and Montana are the states where most avalanche-related deaths happen.

What is a sluff?

A sluff is a layer of loose snow. On rare occasions, an avalanche may be comprised of sluff rolling down a hill, but more frequently it is a dry or wet slab that causes an avalanche.

Most avalanches are triggered simply by gravity acting on heavy snow banks, but sometimes a careless snowmobiler or skier may be the culprit.

Most avalanches are triggered simply by gravity acting on heavy snow banks, but sometimes a careless snowmobiler or skier may be the culprit.

How many people die in the United States because of avalanches?

Deaths from avalanches are fairly uncommon, but they do occur, often as a result of carelessness or from not heeding posted signs. Below is a list of fatalities covering the last decade.

U.S. Avalanche Fatalities from 1998 to 2008

Season

Deaths

1998-1999

29

1999-2000

22

2000-2001

33

2001-2002

35

2002-2003

30

2003-2004

23

2004-2005

28

2005-2006

24

2006-2007

20

2007-2008

36

What is the worst avalanche disaster on record?

In 1970, an avalanche in Yungay, Peru, killed 20,000 people.

What unique weapon was employed during World War I?

During the War to End All Wars, avalanches were deliberately triggered in some battles in Europe as a weapon. Estimates are that between 40,000 and 80,000 soldiers died as a result.

What is the Storm of the Century?

Over the years, a number of storms have been called "storms of the century." The twentieth century experienced several storm events that could certainly qualify, or at least be nominated, for this honor. A huge blizzard struck the Midwest from January 10 to 11, 1975, that included snowfalls in Nebraska reaching 19 inches (48 centimeters) deep, wind chills of -80°F (-62°C) in the Dakotas, and wind bursts of 90 miles (145 kilometers) per hour in Iowa. Eighty lives were lost as a result of this storm.

Another candidate for the title arrived on stage in 1993, when a blizzard struck the American East Coast, killing 318 people, including 48 at sea. Fifty percent of the American population was affected in some way by the storm. The storm reached from Maine to Florida, where half a foot of snow even fell in the Florida Panhandle, and even Daytona Beach saw freezing temperatures. Winds near Key West raged at up to 109 miles (175 kilometers) per hour. Meanwhile, Mount LeConte, Tennessee, saw 56 inches (142 centimeters) of snow, and in Syracuse, New York, there was 43 inches (109 centimeters) of the white stuff.

The 1993 storm ranged far beyond U.S. borders, however, extending north to Canada and south all the way to Central America. At its peak, it reached the strength of a category 3 hurricane, and by the time it was over it had dumped 44 million acre-feet (about 14.3 trillion gallons, or 54.3 trillion liters) of water onto the ground. Add to this several killer tornadoes, and perhaps the 1993 storm wins the twentieth century's title as "storm of the century."

 
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