A radar can only see so much.
As National Weather Service Twin Cities/Chanhassen Warning Coordinator and Meteorologist Todd Krause explained, it takes reliable and alert storm spotters to know what’s really going on.
Krause was speaking during a storm-spotter training for Rice County Skywarn Thursday night at Buckham West Library in Faribault.
“We’re looking at the radar, whereas storm spotters are actually looking down near the ground,” he said. “And that’s where you can actually see whatever’s going on.”
Skywarn is a nationwide program with storm spotters dedicated to providing on-the-ground updates and information about severe weather to the National Weather Service and the public. Anyone can be a spotter, but have to attend a free training session, like Thursday’s session.
Storm spotters report anything they see, but also what they can’t see. Krause said “uncertainty is OK,” referring mostly to tree lines blocking the view of the storm.
Faribault Fire Chief Dusty Dienst sometimes gives similar storm-spotter training to his firefighters, which he said helps them “get an early warning,” since they’ll likely need to be dispatched if a tornado hits.
Dienst said Krause was his own storm-spotting trainer, and he was excited to see he was willing to make the trip to Rice County to lead the session. Normally, Dienst would be leading the sessions.
As that training went on, it became clear why the NWS would need to see the lower part of the storm. Because that’s where the action is.
A storm forms when hot, humid air rises. As the moisture from the rising air is condensed, it becomes a visible, cauliflower-like cloud called a cumulus cloud. Once it reaches a certain height, it cools and comes back down.
This cycle can vary greatly in terms of speed. The faster it goes, the worse things can become. Especially when it starts spinning horizontally.
Static from the condensation creates lightning, the falling condensation can be rain or hail and, as the rotation picks up speeds, the risk of a tornado increases greatly.
As the updraft becomes stronger and humidity is sucked into it, rapid condensation forms in one spot quicker than the rest of the storm. This is known as a wall cloud. If that rotation continues to strengthen, a funnel cloud can form.
Then, if the rotating updraft builds up enough power, it blasts further and further down. Once it gets low enough and begins moving debris on the ground, the storm officially has a tornado.
While some indicators are visible on radar, almost all this activity is shrouded by the clouds overhead. This is why the NWS needs on-the-ground reports from its storm spotters.
Faribault resident Ken Warwick has attended storm-spotter training in the past, though he never really participated in the program. However, now that he’s retired, he wanted to get back into it. So he went to the training session too.
He said Krause did an especially good job at explaining the purpose of storm spotters and the stages from first rotations to a full-blown tornado.
“That radar beam doesn’t tell you what’s going on the ground,” he said. “You actually need human beings on the ground who are willing to volunteer to fill in the blank and give people a few more minutes to get to safety.”
But that’s not the only reason, Krause noted.
“If our warning says that tornadoes have been seen or there’s been damage reported from the storms, a lot more people will take shelter,” Krause said. “As opposed to us saying a warning such as ‘Radar indicated there may be a tornado.’ But when there actually are tornadoes reported, more people actually get to shelter.”
To see info on future training sessions, visit facebook.com/RiceSkywarn or skywarn.us .
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