AUSTIN, Texas - I am sure you've heard people say, "The National Weather Service will be surveying the area for damage before determining if the tornado was an EF 1,2,3," and so on. But what is it that they are looking for to clue them in on the intensity of a tornado?
Let's start with EF0 with winds of 65 - 85 mph.
This is considered minor damage and about half of all tornados are determined EF0. With an EF0, they look for branches broken off trees, peeled surfaces off some roofs, damage to gutters or siding, and pushed over shallow-rooted trees. Also, tornados that remain in open fields with no reported damage are EF0.
On to EF1 tornadoes with winds from 86-110 mph or moderate damage.
About 30% of reported tornadoes fall into this category. The aftermath includes severely stripped roofs, windows/glass broken, exterior doors ripped off, and mobile homes becoming overturned or badly damaged. The tornadoes on March 21, 2022, in Jarrell and Giddings are in this category (SO FAR).
EF2 winds are 111- 135 mph/ considerable damage. About 10% of tornadoes are EF2s. The damage includes roofs ripped from homes, mobile homes totaled, large trees snapped or uprooted, and the vehicles are lifted off the ground as we saw in Bastrop County.
EF3 - Severe damage with winds of 136-165 mph.
About 3.5 percent of tornadoes fall into this category. The survey team looks for entire stories of homes ripped off, damage to large buildings, bark ripped off trees, heavy cars lifted and thrown, and overturned trains.
EF4- Extreme to near-total destruction- winds are 166 to 200 mph. About .7 percent of tornados fall into this category. This is where heavy cars are thrown long distances, well-constructed homes, and whole frame houses are entirely leveled.
And finally, the most deadly and rare EF5 tornado with winds of over 200 miles an hour, accounts for less than .1% of tornado reports. It falls under the massive damage category.
The aftermath includes substantial frame houses lifted off their foundations and swept away. Steel reinforced concrete structures are critically damaged, and high-rise buildings suffer severe structural distortion.
In 1997 Jarrell in Williamson County faced an EF5.
The peak of tornado season in the Austin area is in May, so now is the time to make sure that you and your family have a plan.
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