Most people who have lived in snowy areas understand that snow can be locally heavy and that a lot of snow can fall in a short amount of time. Three kinds of snowstorms that produce such a large amount of show in a brief time are snowbursts, whiteouts, and blizzards. The confusing part is that these aren’t different words to describe the same thing, though they are definitely connected.
The three words actually describe three different kinds of snowstorms, all of which usually have the same end result; a large accumulation of snow in a short period.
In a whiteout, often referred to as ‘whiteout conditions’, the snow falls so hard that visibility is usually less than a quarter-mile, often much less. In fact, at times the visibility can be a few feet. A person in a whiteout cannot clearly make out the horizon and can easily get lost because they are unable to distinguish landmarks. Hypothermia is a real threat if that happens.
Whiteouts are usually accompanied by winds, which blow the snow and make matters worse. It isn’t uncommon for the winds to exceed 30 miles per hour for brief times, though the wind speeds are normally somewhat less than this. Over a foot of snow accumulation per hour is possible in a whiteout.
A blizzard is similar to a whiteout in a number of ways. The horizon can’t be seen because the snow is falling so hard and there is always a wind associated with the storm. Visibility is usually very poor. Additionally, blizzards can also dump over a foot of snow per hour.
However, an important difference between a blizzard and a whiteout is that in a blizzard, the wind speed is above 30 mph constantly during the snowstorm and the sustained 30 mph winds blow for at least 3 hours.
One of the biggest hazards of blizzards, though many people don’t think about it, is drifting snow. Drifting snow is a natural consequence of heavy snowfall with a strong sustained wind that causes the snow to be blown along in a horizontal direction until it reaches an obstruction. It then backs up behind the obstruction, sometimes to amazing depths.
A snow drift at Crater Lake National Park had a depth of about 75 feet and it was formed in a matter of just over two days. This is not an uncommon occurrence in places that get both heavy snowfall and strong winds. Snow drifts also happen with whiteouts, although normally not to the same extent as in a blizzard.
A snowburst is a lot like both whiteouts and blizzards. That is, the horizon can’t be seen, visibility is quite poor, and snowfall is heavy. The distinguishing factor is the wind, or in the case of a snowburst, the lack of it.
Snowbursts are incredibly intense snowstorms that usually don’t last much longer than a day or two, though they’ve lasted four days at times. There is very little or no wind involved, so the snow falls more or less straight down, covering everything in a deep blanket of snow.
Snowbursts are associated with lake-effect snow. The storm that the word was first applied to lasted four days and dropped over six feet of snow, although there was no wind. During that storm, in a 24-hour period, about three and a half feet of that six feet of snow fell. Not surprisingly, the location of that storm was Oswego, New York, and the storm was spawned by lake-effect off of the Great Lakes.
More briefly, if there is a heavy snowfall from a storm and during that snowfall, there are winds of over 30 mph for at least 3 hours, it is a blizzard. If there is a heavy snowfall that includes windy conditions, but those winds are not over 30 mph for 3 hours or longer, it is a whiteout. If there is a heavy snowfall with little or no winds, it is a snowburst.
All three usually dump a great deal of snow in a relatively short amount of time. All three can also be quite dangerous for a secondary reason other than getting lost or buried in the snow. During these storms, many structures collapse and rooves cave in because of the enormous weight of the snow. People can be crushed when this happens. Power outages also happen frequently during all three because power poles are knocked over and powerlines are snapped.