email
print
Thundersnow
From CopperWiki
Thundersnow is a rare and little-known phenomenon which takes place when thunder and lighting occur during a snowstorm. It appears most often in late winter or early spring. In thundersnow precipitation comes down in the form of snow instead of rain.
Contents |
[edit] Why should I be aware of this?
- Thundersnow can help make weather forecasts. After thundersnow storms are tracked, researchers release weather balloons, which are meant to reveal how the atmosphere becomes unstable. By collecting data on pressure, temperature, humidity, and wind speed and direction—the five key factors meteorologists use to make predictions — it is expected that thundersnow studies can help make future weather forecasts more accurate.
- Thundersnow has been recorded in a variety of places around the world, including China and Japan.
[edit] All about thundersnow
There are usually three forms of thundersnow:
- A normal thunderstorm on the leading edge of a cold front or warm front that either forms in a winter environment or one which runs into cool air and maintains the precipitation as snow.
- A heavy synoptic snowstorm in the comma head of an extratropical cyclone that sustains strong vertical mixing which allows for favorable conditions for lightning and thunder to occur.
- A lake effect or ocean effect thunderstorm which is produced by cold air passing over relatively warm water, this effect commonly produces snow squalls over the Great Lakes.
The most common factor is lake or ocean effect snowstorms which occur when cold air passes over a warmer body of water.
To get things started you need convection, which is the up and down movement of air. In every thunderstorm negative and positive charges need to be separated to build an electrical field that's strong enough to create lightning. If the temperature contrast between the cold air and the warm water of a lake is large enough, lake effect snow is created.
The more violent the convection is, the greater the likelihood of lightning and thunder while it's snowing.
[edit] Thunderstorm and thundersnow
In thunderstorms which occur during summer, the atmosphere is stacked up in two layers. The lower layer is full of warm, moist air; the upper layer is icy cold and dry. Because hot air rises, there are soon tremendous updrafts, carrying the warm moisture of the lower layer up into the cold, dry layer. The turbulence of these updrafts creates static electricity as the air masses rub against each other. Thunder and lightning occur when the static electricity discharges in a giant bolt of electricity.
In the winter, the lower layer is likely to be a lot colder and drier than it is in the summer. It's much harder to get the sharp divisions in the atmosphere that lead to turbulence, static electricity, and thunder. It can happen though, especially near the coast. A thunderstorm can form over the relatively warm and most air over the ocean, then move into the icy atmosphere over the land. When this happens, there’s a sharp atmospheric division in a snow storm, and a thundersnow follows.
[edit] What can I do?
- Stay indoors throughout the duration of the storm.
- Kids have atendency to run out when they see snow. Prevent them from venturing out.
- All the variations involved in thundersnow make it frequently dangerous if you're caught out outdoors when it happens.
[edit] 90 degrees
One unique aspect of thundersnow is that the snowfall acts as an acoustic suppressor of the thunder. The thunder from a typical thunderstorm can be heard many miles away, while the thunder from thundersnow can usually only be heard within a two to three kilometer radius from the lightning. In the United States, March is their peak month of formation, and on average, only three events are reported per year.
