What’s a derecho? Our weather expert breaks down the mess

Jul 29, 2021 at 08:04 PM CDT

Straight Arrow News

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The midwest experienced some severe thunderstorms that resulted into derechos. Meteorologist, Sven Sundgaard broke down what about the what happened in Wisconsin and Illinois.

Straight Arrow News

Tags: Climate Change

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TAYLOR KNIGHT:

HEY, EVERYONE, IT’S TAYLOR KNIGHT AT STRAIGHT ARROW NEWS. TODAY I’M INTERVIEWING WITH CERTIFIED METEOROLOGISTS, SVEN SUNDGAARD. HE’S GOING TO BREAK DOWN WHAT’S GOING ON IN THE MIDWEST WITH SEVERE THUNDERSTORMS AND DERECHOS. BUT FIRST, LET’S START OFF WITH WHAT ARE THE DERECHOS.

SVEN SUNDGAARD:

SO THE DERECHOS LITERALLY COME FROM A SPANISH WORD DERECHO MEANS STRAIGHT LINE. SO WHEN WE REFER TO STRAIGHT LINE WINDS, WE’RE TALKING ABOUT THE DERECHOS. AND, YOU KNOW, THE UPPER MIDWEST GETS MORE OF THESE THAN ANY OTHER PLACE ON THE PLANET. SO IT’S A UNIQUE PART OF THE WORLD FOR THIS TYPE OF STORM.

TAYLOR KNIGHT:

OKAY, SO WHAT KIND OF DAMAGE DO THEY DO? ARE THEY SIMILAR TO THUNDERSTORMS OR TO HURRICANES? WHAT CAN WE EXPECT WITH IT DERECHO.

SVEN SUNDGAARD:

SO DERECHO IS A TYPE OF THUNDERSTORM. GENERALLY, THE SEVERE TYPE OF THUNDERSTORMS WE SEE IN THE US, AND ESPECIALLY THE UPPER MIDWEST ARE EITHER SUPER CELLULAR THUNDERSTORMS, WHICH ARE INDIVIDUAL CELLS, THE THEY ARE OUR NUMBER ONE TORNADO PRODUCER, AND PROVES THE BIGGEST TORNADOES, DERECHOS ARE CAN START TO SUPERCELLS, WHICH IS WHAT HAPPENED LAST NIGHT, ACTUALLY ACROSS PARTS OF WISCONSIN, INDIVIDUAL CELLS THAT WERE SUPER CELLULAR, AND THEN THEY MERGE AND FORM OF A LINE AND THEY START TO PRODUCE WHAT WE CALL A BOW ECHO, IT LITERALLY LOOKS LIKE A THINK OF A BOW AND ARROW, WHERE IT’S ONE LONG LINE OF WIND. AND THOSE WINDS CAN GET PRETTY GUSTY HURRICANE FORCE DEFINITELY OVER 74 MILES AN HOUR IS WHAT QUALIFIES AS A HURRICANE. AND THEY’RE ACTUALLY MORE DAMAGING THAN A TORNADIC STORM. BECAUSE A TORNADO YOU THINK OF IT IS SORT OF HIT AND MISS HAS AN NARROW PATH. MAYBE SOMETIMES IT’S A LITTLE WIDER, BUT ITS DERECHO CAN BE OVER DOZENS OF MILES AND CAN LAST FOR HOURS. SO THE STORMS WE SAW LAST NIGHT, FOR EXAMPLE, LASTED MUCH OF THE NIGHT STARTING IN NORTHWESTERN WISCONSIN SWEPT ACROSS THE WHOLE STATE ALL THE WAY PAST CHICAGO, SO THEY’RE LONG IN DURATION. AND BECAUSE THEY’RE SO ORGANIZED, THAT THAT WIND THAT BOW ECHO ACTS LIKE A SORT OF A COLD FRONT, AND IT PUSHES THE WARM, HUMID AIR UP AHEAD OF IT INTO THE STORM. SO THE STORMS DON’T RAIN ON THEMSELVES, YOUR AVERAGE THUNDERSTORM BUILDS, THE RAIN COMES DOWN, IT COLLAPSES. IT’S LAST MAYBE 2030 MINUTES. BUT THESE ORGANIZED STORMS LAST FOR HOURS BECAUSE THEY’RE ABLE TO SEPARATE THE COOL FOR THE RAIN COOLED OUTFLOW AND THE WARM, HUMID INFLOW.

TAYLOR KNIGHT:

WOW. OKAY. SO I KNOW YOU MENTIONED BRIEFLY THAT IT WOULD HIT WISCONSIN AND KIND OF THE CHICAGO AREA, WOULD YOU SAY THAT’S WHY IT’S SUCH A BIG TALK RIGHT NOW, FROM WHAT HAPPENED LAST NIGHT.

SVEN SUNDGAARD:

OF COURSE, WHEN THESE THINGS HIT CITIES THERE, THEY MAKE BIG NEWS, CHICAGO, OBVIOUSLY BEING THE THIRD LARGEST CITY IN THE COUNTRY. BUT IT’S ALSO IT AFFECTS PEOPLE IN SEVERAL WAYS. IT’S NOT JUST TREES DOWN. BUT WHEN YOU HIT IN DENSE URBAN AREA, ALL THOSE TREES DOWN CAUSE PROBLEMS BECAUSE IT’S BLOCKING ROADS, IT’S FALLING ON POWER LINES. SO THERE’S POWER OUTAGES. SO THERE’S A LOT MORE IMPACTS. BUT YOU KNOW, LAST SUMMER, PEOPLE MIGHT REMEMBER, WE HAD A BIG DERECHO THAT WENT ACROSS IOWA, OBVIOUSLY NOT AS MANY BIG CITIES, BUT IT DESTROYED SO MANY FARM FIELDS, THAT IT BECAME A BIG ECONOMIC IMPACT. AND A BIG TALKER, TOO. BUT IT TOOK LONGER. IT TOOK DAYS OR WEEKS FOR MOST AMERICANS TO NOTICE UNTIL IT MADE THE NEWS BECAUSE IT DIDN’T KILL PEOPLE DIDN’T DO AS MUCH DAMAGE TO STRUCTURES, BUT IT HAD A HUGE IMPACT ON THE ECONOMY.

TAYLOR KNIGHT:

WOW. AND THEN HOW CAN PEOPLE PREPARE FOR THIS? BECAUSE YOU SAID ALL THOSE DAMAGES THAT HAPPENED IN IOWA LAST YEAR? HOW DOES SOMEONE PREPARE FOR A DURATION?

SVEN SUNDGAARD:

YEAH, IT’S TOUGH. IT’S SIMILAR TO WHAT HAPPENS IN A TORNADO, YOU WANT TO GET INTO THE LOWEST LEVEL OF YOUR YOUR HOME OR BUILDING AWAY FROM WINDOWS? BECAUSE THESE ARE HURRICANE FORCE WINDS. OFTENTIMES, NOW IT DOESN’T LAST AS LONG AS A HURRICANE. USUALLY, WE’RE TALKING ANYWHERE FROM 30 SECONDS TO A MINUTE THE WORST WIND GUST, YEAH. AND THEN IT JUST POURS RAIN FOR A WHILE. BUT THE ACTUAL STRONGEST WINDS ARE PRETTY SHORT. IT’S A QUICK MINUTE OR SO. BUT IT DOES VERY SIMILAR THINGS AS TO A TORNADO TREES DOWN STRUCTURAL DAMAGE, BUT IT’S IN A STRAIGHT LINE. SO WHEN WE TRY TO FIGURE OUT WAS IT A TORNADO OR STRAIGHT LINE WINDS THAT DID THIS, ONE OF THE BEST WAYS IS TO LOOK FROM THE AIR TORNADIC DAMAGE IS ALL OVER THE PLACE. AND YOU CAN TELL THAT STUFF WAS JUST MOVING IN ALL DIRECTIONS, BUT PARTLY WHY WE CALL THEM DERECHOS OR STRAIGHT LINE IS BECAUSE THE DAMAGE IS ALL IN ONE STRAIGHT LINE. THE TREES ALL GO DOWN A CERTAIN WAY THE CORN ALL LIES A CERTAIN WAY. SO YEAH, IT’S SIMILAR WAYS TO PREPARE FOR THAT. AND YOU KNOW, ONE OF THE PROBLEMS WITH THESE IS THEY DO OFTEN OCCUR AT NIGHT. SO FOR EXAMPLE, MY SISTER LIVES IN MILWAUKEE. SHE TEXTED ME AT 130 IN THE MORNING, THE SIRENS ARE GOING OFF. WELL, YOUR METEOROLOGIST BROTHER WAS FAST ASLEEP AT THAT POINT. BUT YEAH, IF THEY’RE IF THEY’RE TALKING ABOUT THE POSSIBILITY OF THESE STORMS, YOU WANT TO STAY ALERT. YOU DON’T HAVE TO STAY UP ALL NIGHT BUT MAYBE KEEP THE SOUND DOWN ON YOUR PHONE OR HAVE SOME WAY TO GET ALERTS SO THAT YOU CAN GET YOURSELF OR YOUR FAMILY SAFELY TO A TO A SAFE SPOT IN YOUR HOME. BUT YEAH, THEY CAN BE KIND OF FREAKY IN THAT THEY DO OFTENTIMES HAPPEN IN THAT WEIRD ONE TO 4AM TIMEFRAME, WHICH IS OBVIOUSLY HARDER TO STAY ALERT.

TAYLOR KNIGHT:

WELL, THANK GOD YOUR SISTER HAS YOU TO GIVE THAT QUICK CALL.

SVEN SUNDGAARD:

I WAS ASLEEP WHILE YOU’RE SLEEPING,

TAYLOR KNIGHT:

BUT FOR FUTURE, I’M SURE IT COMES IN HANDY.

SVEN SUNDGAARD:

YEAH, YOU KNOW, AND ONE OF THE THINGS I WANT TO SAY, THERE IS A LOT MORE WARNING TIME HOURS IN ADVANCE ON THESE THINGS. SO THE WEATHER SERVICE, THE STORM PREDICTION CENTER YESTERDAY WAS TALKING ABOUT THIS POSSIBILITY ALL DAY YESTERDAY. SO NOBODY SHOULD HAVE BEEN COMPLETELY SURPRISED. WE KNEW THAT THIS WAS A POSSIBILITY. AND THAT’S COME A LONG WAY. IN 10-20 YEARS, WE’VE GOTTEN A LOT BETTER WITH THAT SHORT TERM FORECASTING OF STORMS WITHIN A 24 HOUR PERIOD. SO THERE’S A LOT MORE LEAD TIME ON THESE THINGS.

TAYLOR KNIGHT:

THAT’S GOOD. I’M SURE IT’S ALWAYS BETTER TO BE PREPARED THAN NOT HAVE ANYTHING, YOU KNOW, PLANNED OUT AND FIGURED OUT BEFOREHAND. SO THANK YOU SO MUCH FOR SHARING THIS INFORMATION WITH US TODAY. I’M SURE THE AUDIENCE AND MYSELF LEARNED A LOT ABOUT THE DERECHOS.

SVEN SUNDGAARD:

ABSOLUTELY. YOU KNOW, IN LATE SUMMER IS TENDS TO BE THE PEAK TIME FOR THESE TWO.

TAYLOR KNIGHT:

OH, AND IT’S SUMMERTIME. SO THAT’S DEFINITELY KEEP YOUR EYES OUT. WOULD YOU SAY THIS IN THE MIDWEST AREA, TYPICALLY THAT THESE STORMS TAKE PLACE.

SVEN SUNDGAARD:

THEY CAN’T HAPPEN IN THE EAST. BUT YOU KNOW, THE UPPER MIDWEST, WE SEE MORE OF THESE THAN ANY OTHER PART OF THE WORLD. SO YEAH, MINNESOTA, IOWA, THE DAKOTAS, WISCONSIN, ILLINOIS, EVEN TOWARDS MICHIGAN, MISSOURI, ALL THAT UPPER MIDWEST REGION, WE DO SEE A LOT MORE OF THESE THAN OTHER PLACES. OKAY.

TAYLOR KNIGHT:

WELL, THANK YOU SO MUCH FOR SHARING THE INFORMATION WITH US TODAY, FOR TALKING WITH US TODAY. AND I HOPE YOU HAVE A GREAT DAY.

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