Severe weather can strike with little warning in Minnesota’s ‘radar gap’

There was no doubt a storm would blow through northern Minnesota over the weekend. As meteorologists watched the behemoth move across North Dakota and into the state, officials issued alerts in the Bemidji area, including to landline phones and cellphones.

Then straight-line winds up to 120 mph — equivalent to a Category 3 hurricane — walloped the area, toppling trees, tangling power lines and leaving thousands without power during a heatwave.

“This was a 10-mile-wide path that just destroyed Bemidji,” Christopher Muller, director of Beltrami County Emergency Management, said Tuesday. “It’s indescribable as to how much our community has changed. It just does not look the same.”

While the weekend storm was well-tracked due to its height and size making it visible on the radar, a large swath of Minnesota — including the Bemidji area — falls into what is known as a radar gap where storms can crop up with little to no warning.

The radar gap includes much of cabin country and popular camping spots on the northern Minnesota border.

“There are a lot of people that are getting in their campers or going out to their cabins or sending the kids off to camp,” said Ace Bonnema, director of Kandiyohi County Emergency Management.

Bonnema and Muller are part of a group of emergency managers working to get more lower-level radar systems across the state, as well as educate people about the gaps.

It’s personal for Bonnema, who lost an experienced weather spotter three years ago: Ryan Erickson, 63, was killed when a grain bin blew over and crushed him when he was called to monitor ground-level conditions during severe weather.

Most of Kandiyohi County is within an area considered to have diminished radar coverage, meaning no radar from the National Weather Service NEXRAD Doppler systems below 3,000 feet. But many areas, including Bemidji, have no radar below 6,000 feet. And two slivers in the state — a patch in western Minnesota and the Northwest Angle — have no NEXRAD radar coverage below 10,000 feet.

“We’re just trying to get more eyes on the skies,” Bonnema said. “The more radars that we can get out there, the better. And they’re just going to give people more notice.”

The low-level radar would have likely made an impact in the early morning hours of July 4, 2018, when an EF1 tornado struck Bemidji. The county didn’t activate the sirens because the tornado didn’t show up on the radar.

Muller said low-level radar wouldn’t have made much of a difference during the weekend storms because the fronts were so massive. But it might have given officials and first responders a better idea if there was rotation closer to the ground.

“Most severe weather is best detected at the lower elevation of the storm,” Muller said.

The NWS set up its system of powerful NEXRAD systems in the 1990s, including towers in Duluth, Chanhassen and Sioux Falls. The farther an area is from a NWS tower, the greater the radar gap.

“These radar beams travel in a straight line and the earth is curved. That’s why they’re in the blind spot because the beam is just so high up in the air by the time they get by them,” Sen. Rob Kupec, D-Moorhead, said of areas in the gap.

Kupec, a former television meteorologist in Fargo, co-authored a bill this session to appropriate about $3 million over the next two years for gap-filling radar data from a private company. The Senate bill was co-authored by Sen. Andrew Lang, R-Olivia, and had bipartisan support.

But the bill died this session, which Kupec attributed to the Senate judiciary committee needing to prioritize funding for prisons and court systems during a tight budget year.

Last year, Kupec said he talked with emergency managers and retired NWS staff about whether the state could fund and manage its own system of low-level radar. The cost to do it themselves was estimated at $25 million, he said.

“And then, lo and behold, this private entity shows up,” Kupec said, referring to Climavision, a Kentucky-based company that makes radar systems to help fill the voids.

In October 2023, Climavision partnered with Wendell, a small city in western Minnesota’s Grant County, as part of a pilot project. Climavision installed an X-band radar system on a water tower that now provides coverage for a diamond-shaped part of the state where NWS radar doesn’t reach below 10,000 feet.

The X-band radar is being used by over a dozen county public safety offices, as well as the National Severe Storm Laboratory and NWS forecast offices, according to Tara Goode of Climavision.

Since its installation, it has helped officials forecast a snow squall, which is a brief burst of heavy snowfall that typically hovers in the lower levels of the atmosphere. The phenomena have caused traffic pileups and deaths across the country.

“It was their first snow squall warning ever,” she said. “Not that they didn’t ever have snow squalls, they just normally didn’t get warned in advance.”

The radar also picked up smoke plumes that helped first responders extinguish two small wildfires that could have threatened a handful of nearby homes if they weren’t caught so quickly, Goode said.

Climavision has 29 radars online in 14 states with plans for 200 systems, Goode said. In addition to the Wendell X-band system, the company plans to install radars in Keister, Bemidji, Brainerd and Renville County, and eventually three more along the northern border.

Low-level radar advocates say the new systems would also improve weather predictions in metro areas because the storm systems could be better tracked across the state and not suddenly pop into view closer to the NEXRAD towers.

“It would actually give more lead time to the Twin Cities potentially for storms coming in,” Kupec said.

Climavision covers the installation, maintenance and operations, and its data will be available at no cost to support public safety measures, according to Goode. The company sells radar data to businesses such as insurance, agriculture and media companies.

In the future, the data could be integrated into radar apps and websites for consumer use. As of now, those products predominantly use public data from federally funded infrastructure like the NWS systems.

Lang, the state senator who is also a helicopter pilot for Lifelink, said he thinks obtaining funding through the Legislature in the coming years won’t be difficult since both sides of the aisle support the project. But what might take some time to iron out are specifics of the public-private partnership and ensuring the data would be public.

Lang has been flying in Minnesota for close to three decades and said he experiences the radar gap frequently.

“The incongruity between what we’re seeing in the aircraft on our own personal radar versus what’s showing on NEXRAD … on a very routine basis is quite astounding, to be honest,” he said.

While the aviation community is well aware of the radar gap, Lang finds the general public is not.

“They have to depend on the information they get,” he said. “We have the technology. We have the capability for an early warning system.

“The gap is there. Let’s fix it.”

Kim Hyatt of the Minnesota Star Tribune contributed to this story.

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