Why tall buildings increase wind speeds

On windy days, downtown streets can become veritable wind tunnels, sharply increasing the speed of gusts and in some cases proving dangerous.

The scientific reason for that phenomenon is called the "Venturi Effect."

FOX23 Chief Meteorologist James Aydelott explains it's the same principle that increases the water pressure from a garden hose when you put your thumb over the end of a garden hose.

"When you constrict the air flow, it has to speed up," he says. "That's what's happening with the buildings downtown. It creates little canyons, and it's a big problem with gridded streets."

He said in some major cities, like Manhattan, pedestrians have been blown around and injured, some actually getting pushed through windows by the strong winds.

Steve Piltz with the National Weather Service loaned KRMG a handheld anemometer, a device used to measure wind speed.

The model he loaned us also measures temperature and humidity.

"It's what the fire guys carry with them when they go out on scenes and try to get humidity and wind stuff," he said.

Those factors are important when battling fires, or in incidents involving hazardous materials.

During our visit downtown, we used the anemometer to measure the gusts, and saw wind speeds jump as much as 20 mph when rounding corners in some areas.

The winds were created by a cold front that passed through the area late Thursday morning.