CHICAGO – A massive storm with wind gusts up to 81 mph howled across the nation’s midsection Tuesday, snapping trees and power lines, ripping off roofs, delaying flights and soaking commuters hunched under crumpled umbrellas.

Spanning from the Dakotas to the eastern Great Lakes, the unusual system mesmerized meteorologists because of its size and because it had barometric pressure similar to a Category 3 hurricane, but with much less destructive power.

Scientists said the storm had the force of a blizzard minus the snow.

“If it were colder, we’d have a blizzard with this system,” said David Imy, operations chief at the National Oceanic and Atmospheric Administration’s Storm Prediction Center in Norman, Okla. But temperatures were in the 50s and 60s, instead of the 20s.

The agency said the system’s pressure reading Tuesday was among the lowest ever in a non-tropical storm in the mainland U.S. Spokeswoman Susan Buchanan said the storm was within the top five strongest storms in terms of low pressure.