Refresher for spotters, as Nebraska heads into spring and summer severe weather
BEATRICE - Some northern areas of the U.S. have already had a taste of spring or summer-like severe weather….and the calendar has just turned to March.
"On Monday, we picked up some tornadoes in the Chicago area, farther north than here,,,and I don't know if anybody's caught it, but Wisconsin had a February tornado...and just two years ago, we had December tornadoes. It's almost kind of funny that we still do these in February, March and April."
Brian Barjenbruch, Science and Operations Manager for the National Weather Service in Valley, gave a weather spotter training session Thursday night…along with Meteorologist, Michaela Wood. Gage, Jefferson and Saline Counties Emergency Management put on the session attended by about 60 at the Homestead National Historical Park Education Center, west of Beatrice.
Barjenbruch says the National Weather Service relies on spotters to give the who, what, where and when of severe weather….and to do it safely.
"If you don't take anything away, take this away. If the tornado is getting bigger, it's coming right at you. Sometimes, it just looks like its growing and growing....and then it's a half-mile away. That's a bad spot to be."
Peak season for tornadoes in Nebraska is generally April, May and June….though tornadoes can happen any month of the year. This week, tornadic weather hit parts of Illinois, Wisconsin, Ohio and Michigan. Storm spotter sessions in Nebraska began in early February and will extend through mid-April. They provide information on tornados, hail, severe storm winds and flooding…and what to look for in the structure of storms.
Barjenbruch says the National Weather Service cannot rely on radar alone… thus the need for spotters. "Tornadoes start more or less at ground level. There's rotation higher in the clouds too, but the tornado starts down here. So, unless that tornado is on our office, the radar is just not going to see the tornado itself, really. There's a lot of other things we can do to predict tornadoes. We'd rather have the warning out twenty minutes before the tornado shows up...that's the goal. And so, that's what we're going with.....but the observation is really important."
Severe thunderstorm lines can pack powerful downburst winds of 60-to-80 miles-per hour, occasionally topping 100 mph. A Derecho, a long powerful line of storms that hit Cedar Rapids, Iowa in recent years, had winds of up to 135-miles-per-hour.
Barjenbruch says flash flooding is a threat that can be underestimated. "Even here where it's flat, we get some pretty good rainfall rates. So we can really see that water come up...I'm sure you all have. Within a half hour of a good four inch rain, things are getting ugly pretty quick. The bad thing a lot of times are these washout roads. One of the biggest things that happens is people try to drive through the floodwaters....and it looks flat on the top...and don't realize the road is undercut and washed out....and we end up having a water rescue."
Supercell thunderstorms are among the most powerful and dangerous in Nebraska. Such storms rotate in a column thousands of feet into the air and can produce tornadoes and very large hail…as well as flooding.
Spotters can report severe weather to the National Weather Service by phone, online or on social media. Barjenbruch says pictures or short videos are often helpful.