BANGOR – Though not common, tornadoes do occur in Maine, according to Joseph Hewitt, lead weather forecaster for the National Weather Service office in Caribou.

“Are they common? It seems like we see more and more of them,” Hewitt said Thursday. “I’d say every year, or at least every other year, we have one.”

According to Hewitt, the most recent tornado reported in Maine occurred last summer in the St. John Valley on Van Buren Cove on Long Lake.

Largely because of Maine’s hilly topography, which slows tornadoes down, the ones that have occurred here have been short in duration and relatively weak in strength, racking up 0s on the Enhanced Fujita scale, which ranks tornadoes from 0 to 5 based on degree of intensity and damage.

“We call them little spin-ups,” Hewitt said of the small ones seen in Maine. “They’re lucky if they’re on the ground half an hour.”

When they do happen, tornadoes often occur with little advance warning. The Maine Emergency Management Agency warns residents to keep an eye on the sky during a storm and to stay tuned to television and radio for emergency messages from the National Weather Service, which may give warnings as few as five to 10 minutes before a tornado forms.

The agency says to be alert for:

. Dark, often greenish sky.

. Wall cloud.

. Large hail.

. Loud roar, similar to a freight train.

Some tornadoes appear as a visible funnel extending only partially to the ground. Some are clearly visible while others are obscured by rain or nearby low-hanging clouds.

If you believe you see a funnel cloud, report it to the National Weather Service at 877- 633-6772.

Keeping safe

At the earliest warning, go into a below-ground area with flashlights and a radio. Remain there until you?re informed that tornado danger has passed. Manufactured homes are especially vulnerable and mobile home residents are urged to evacuate to the nearest frame home with a basement.

If an underground shelter is not available, move to an interior room or hallway on the lowest floor and get under a sturdy piece of furniture.

. Stay away from windows.

. Get out of automobiles. Do not try to outrun a tornado in your car; instead, leave it immediately.

. If caught outside or in a vehicle, lie flat in a nearby ditch or depression.

Information provided by Maine Citizen Alert System.