Daily Archives: April 21, 2008

A tornado still fresh in Hoisington’s memory

Today marks the seventh anniversary of the large night-time tornado that struck Hoisington in northern Barton County, killing two people and injuring 28 others.

The tornado touched down a mile southwest of Hoisington at about 9:15 p.m., rapidly grew to F-3 intensity and entered the west side of town. Within a couple of minutes, it grew to an F-4 and carved a path of destruction two miles long and two blocks wide through the northern part of the city, which has a population of about 3,000 people.

By the time the tornado exited on the north side of the city, officials estimated that it destroyed 182 homes and 12 businesses and tore the roof off of the hospital. As it weakened, it curled back to the northwest and damaged two farmsteads before dissipating.

If that curl back to the northwest sounds familiar, it should: the massive tornado that struck Greensburg last May also turned to the northwest shortly before falling apart - nearly doubling back to strike the town a second time.

The Hoisington tornado alarmed meteorologists because it grew so strong so quickly after touching down. Here’s an excerpt from a story I wrote a few days after the tornado, quoting Dick Elder, meteorologist-in-charge of the Wichita branch of the National Weather Service:

The largest tornadoes - such as the ones that struck Hesston in 1990, Haysville, Wichita and Andover in 1991 and Haysville and Wichita again in 1999 - routinely dip down a few times before gaining strength and staying on the ground for extended periods.

But the Hoisington tornado went from infant to monster in seconds: Less than half a mile from where it touched down just west of the city, the tornado developed wind speeds exceeding 200 mph.

“In all my years of doing this, I’ve never seen one do that that quickly,” Elder said. “That’s something I’ll never forget as long as I live.

“Even if we would have said ‘Tornado Warning, a tornado is on the ground,’ it wouldn’t have done Hoisington any good, because it was so close to the town,” he said.

What kept the tornado’s death and injury toll so low, meteorologists said, is that Hoisington residents were paying attention to the conditions and telecasts about the threatening weather and took shelter before the tornado hit.

Monday’s cap figures to keep a lid on severe weather

NOAA’s Storm Prediction Center has portions of Oklahoma, Kansas and Missouri under a slight risk for severe weather today. The sector of the Sunflower State included is essentially everything east of the Kansas Turnpike.

While forecasters say tornadoes are possible in Oklahoma if the thunderstorms are isolated enough (and thus do not steal energy from each other), the primary threat for Kansas is large hail and strong winds. The threat of tornadoes in Kansas is minimal at best because a “cap” is in place that figures to inhibit the development of strong thunderstorms.

A cap is a layer of warm air sitting atop a layer of cooler air next to the surface. Normally, air rises as it warms up. Clouds form when that warm air reaches upper levels of the atmosphere and the moisture within it condenses. That cap of warm air serves as a set of brakes for the rising warm air, keeping it from breaking through to the upper atmosphere and forming strong thunderstorms.

Caps erode when cooler air reaches that layer of warm air, opening the door for supercell thunderstorms to develop. But forecasters say the cap over Kansas today is pretty strong, shutting the door on the formation of tornadoes.