Tornadoes are one of nature's most dangerous storms. They can wreak havoc on homes and communities, killing and injuring people.
They form on days that are favorable for thunderstorm development, when the air is warm and humid. Strong wind shear, especially in the lower levels of the atmosphere, is also a factor.
Waterspout tornadoes are weaker than land tornadoes, but they can still cause damage to your boat or home. To avoid waterspouts, watch the marine weather forecast and stay away from the water during storms.
Tornadic waterspouts are often accompanied by severe thunderstorms, hail, and strong winds. They form from cumulonimbus clouds and can move onshore like a tornado.
Fair weather waterspouts, on the other hand, develop from a line of cumulus clouds that have dark flat bases, generally without a thunderstorm behind them. They usually dissipate rapidly when they make landfall, and rarely penetrate far inland.
During the summer, watch for a line of cumulus clouds with dark, flat bases, as these can be potential areas for a waterspout to form. Dark spots in the water or sudden shifts in wind direction and speed are also possible warning signs of a waterspout.
When a waterspout is spotted, steer your vessel at a 90-degree angle to its direction of motion. If the waterspout is headed towards your vessel, take down sails, close hatches, and seek shelter below deck.
One dramatic video shows a waterspout blowing ashore in Galveston. It ripped through a group’s beach setup and tossed towels and blankets into the air.
Waterspouts are common along the upper Texas coast and do not require thunderstorms to form, according to the National Weather Service. They usually last only a few minutes, do little if any damage and have winds under 100 mph.
In the most extreme cases, they can move inland as tornadoes and cause significant damage. But, they rarely do.
The most violent tornadoes are those classified as EF-4 or EF-5, with wind speeds between 111 and 165 mph. They can last 20 minutes or more and are rare in southeast Texas.
They are spotted when funnel clouds drop from the bases of cumulus clouds offshore and appear as dark spots in the water. They usually start to form on days with fair weather conditions and a light E/NE'ly wind.
Tornadoes are one of nature's most dangerous storms. They can rip out roofs, lift homes to the sky and throw cars hundreds of feet.
Texas is among the highest tornado-prone states, with an average of 132 twisters touching down each year. But the frequency varies from year to year, especially around cities like Dallas and the Red River Valley, known as "Tornado Alley."
The most common time for tornadoes to occur in Texas is during the springtime. That's because tornadoes need a combination of warm, moist air, cool dry air and wind shear to form.
To find out if a tornado is on the way, you should look for rotating funnel-shaped clouds, low-lying cloud cover, large hail and a dark or green-colored sky.
A strong thunderstorm system that dumped heavy snow on California and Oregon moved eastward Thursday night into the Southeast, causing tornadoes in Texas and Louisiana. The National Weather Service issued a tornado watch for parts of those two states through late Friday.
Wind shear can help or hurt the formation and life of storms. It can make tropical cyclones weaker or stronger and it can even rip them apart completely.
Weather forecasters look at directional wind shear when tracking hurricanes and severe weather. It occurs when winds change direction over a short distance, usually vertically or horizontally.
This type of shear can occur when a cold air mass (such as an inversion) separates cooler low-level air from warmer upper-air air. It prevents the two air masses from mixing, which means that pilots can encounter substantial airspeed changes as they travel through these decoupled layers.
Nonconvective or fair-weather windshear can be quite strong as well, typically caused by an inversion. It’s most common at night, when the ground becomes cooler than the overlying airmass, forming a nocturnal inversion.