Six-people were-killed,,21,vehicles-collided and the Montana's Highway Patrol Sgt.

Six-people were killed Friday night on Montana's Interstate 90 in a dust storm triggered.

 21,vehicles collided and the Montana Highway Patrol Sgt.Jay Nelson said authorities believe the weather is the cause.

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by gusts of more than 60 miles per hour, authorities said.21 vehicles collided and Montana Highway Patrol Sgt.

ause."It looks like there was a zero visibility dust storm caused by high winds," he said.The highway patrol did not immediately count the number of injuries, but Nelson said additional ambulances must be called from Billings for help.The roots of the dust storm go back to a few hours before it erupted in south-central Montana between 1 and 5 p.m. m.According to Nick Vertz of the National Weather Service, it began to move slowly east in MR and at 2 p.m. MR.Billings Meteorologist.The storm resulted in a severe storm warning that covered Hardin and other parts of Montana from mid-afternoon to 9 p.m. Friday.

Forecasters predicted the possibility of isolated coin-sized hail, sporadic gusts up to 75 mph, and frequent lightning strikes. At 4:15 p.m. m., a 40 mph gust was recorded at the nearby Big Horn County airport.

When the airport weather station measured at 4:35 p.m., the gusts reached 100 km/h.Another reading 20 minutes later recorded a 64 mph gust.Wind easily picked up dust from recent temperatures in the 90s and triple digits last week and reduced visibility to less than a quarter mile."If you look up at the sky while you're at Hardin, you'll hardly see anything above the storm clouds that comes to mind," Vertz said."It's just the wind from somewhere."