Severe storms produced hurricane-force winds in Mid-MO on the Fourth

Mid-Missouri is still cleaning up after severe storms tore through the region on the Fourth of July, and a new damage survey shows just how powerful those winds really were.

The National Weather Service reported Monday afternoon that it found evidence of straight-line winds up to 105 mph east of Jefferson City along the Missouri River. That's stronger than some landfalling hurricanes, and it lines up with the worst damage reported on the holiday.

Straight-line winds of that intensity are usually the result of a downburst: a powerful column of sinking air within a thunderstorm that slams into the ground and spreads out in every direction.

Downbursts form when heavy rain and hail create a pocket of cold air inside a storm. Colder air is heavier, and it accelerates downward. When it hits the surface, it has nowhere to go but out, producing damaging winds that can rival or exceed a tornado's.

The size of the damage swath also matters. A downburst spread over several miles is often classified as a macroburst, indicating widespread straight-line wind damage. Smaller pockets of high winds are called microbursts.

Longer-lived downburst events tend to produce more uniform, straight-line tree damage, which is one of the key clues survey teams use to rule out a tornado.

The Storm Prediction Center logged 75 preliminary reports of wind damage on the holiday alone. Osage City sat directly in the storm's path and had to be closed to the public after debris rendered roads impassable.

Thousands of Ameren Missouri customers remained without power as of late Monday afternoon, concentrated mainly in Osage, Cole, Miller, Morgan, and Camden counties. Ameren says power should be fully restored by Tuesday night.

Hundreds of additional customers served by Mid-Missouri electric co-ops are also still in the dark.