Severe Weather Awareness: Thunderstorms and Lightning

Listen to Leon ...

May 1, 2012

Summertime in Maine: Beautiful and dangerous

Summertime is a good time for outdoor recreational activities in New England. It is also the time of the year when thunderstorms are most likely. Thunderstorms can be beautiful, but they also can be deadly. While many people think they are aware of the dangers of thunderstorms and lightning, the vast majority are not.

There are three basic ingredients needed for the formation of a thunderstorm. They include:

Low-level moisture,
An unstable atmosphere, and
A trigger (a source of lift)

Low-level moisture is needed for cloud formation, growth, and the development of precipitation within the cloud.

An Unstable atmosphere allows warm, moist air near the ground to rise rapidly to higher levels in the atmosphere where temperatures are below freezing. An unstable atmosphere also allows air at higher levels in the atmosphere to sink to the ground level rapidly, bringing stronger winds from the higher levels to the ground.

A trigger is something to set the atmosphere in motion.

All three ingredients contribute to the formation of a thunderstorm. In fact, as the magnitudes of these ingredients increase, so do the chances that a thunderstorms could become severe.

Recognize the signs of a coming storm

In the summertime, listen to the latest forecast and learn to recognize the signs that often precede thunderstorm development.

Warm muggy air is a sign that ample low-level moisture is available for thunderstorm development.
Towering cumulus clouds indicate an atmosphere that is, or is becoming, unstable.
And, the trigger could be continued heating from the sun, an approaching front or sea breeze front or a cooling of the upper atmosphere.

All thunderstorms go through various stages of growth and development. As a thunderstorm cloud continues to grow, snow and ice begin to form in the middle and higher levels of the cloud where temperatures are below freezing, and electrical charges start to build up within the cloud.

Negative electrical charges near the middle of the thunderstorm cloud causes a positive charge to build up on the ground under and near the thunderstorm. Finally, when the difference between these charges becomes too great, a giant atmospheric spark we call lightning occurs.

Lightning: An underrated killer

Lightning is an underrated killer, usually claiming its victims one at a time. Lightning also leaves many victims with life-long serious injuries. Lightning can strike as far as 10 miles from the side of the thunderstorm cloud.

In fact, many lightning victims are struck before the rain arrives or after the rain has ended. Many victims also report that at least a portion of the sky was blue when they were struck.

Although Maine and New Hampshire have less lightning than most states east of the rocky mountains, Maine ranks 8th highest in the country in terms of lightning casualties (per capita) and New Hampshire ranks 16th highest.

This summer, the National Weather Service will conduct a nationwide awareness campaign to reduce the number of deaths and injuries from lightning. Although more information on lightning and lightning safety will be provided during Lightning Safety Awareness Week that will be during the week of June 24-30, here are some basic tips to help keep you and your family safe this summer.

While inside a home or building

Avoid any contact with electrical or electronic equipment or cords that are plugged into the electrical system.
Avoid any contact with corded phones.
Avoid any contact with the plumbing system. Do not wash your hands, do not wash the dishes, do not take a shower, or do not do laundry.
Do not stand next to a concrete wall and do not lie on a concrete floor. 5. Stay away from windows, outside doorways, and porches.

Tips while outdoors

There is no safe place outside in a thunderstorm. To be safe, you must get inside a substantial building or hard-topped metal vehicle.
Plan outside activities so that you minimize the risk of being caught outside in a thunderstorm.
If you hear thunder, move inside a safe shelter immediately. Generally, if you can hear the thunder, you're within striking distance of the storm.
If the sky looks threatening, move inside immediately. Don't wait for the first flash of lightning. It could occur anywhere under or near the storm.
Stay inside a safe shelter for at least 30 minutes after the last rumble of thunder was heard. Many lightning victims are struck after the worst part of the storm has passed.

Remember, when it comes to thunderstorm safety, it is your own actions that will determine your personal risk of being killed or seriously injured by the hazards that accompany thunderstorms.

Severe Weather Awareness Week ...

The National Weather Service has declared the week of April 30th through May 4th Severe Weather Awareness Week in New England. Today's message is presented in partnership with the National Weather Service Forecast Offices in Maine:

National Weather Service Gray: covers western and Southern Maine, include York, Cumberland, Sagadahoc, Lincoln, Knox, Waldo, Androscoggin, Oxford, Franklin and Kennebec Counties, and central and southern Somerset County.
National Weather Service Caribou: covers eastern and Northern Maine, including Aroostook, Penobscot, Washington, Hancock, Piscataquis and northern Somerset County.

MAINE EMERGENCY MANAGEMENT AGENCY