NOTE:  The photo shows a starship that stopped the tornado from touch-down near Rapid City, SD.  As I have said, we are protected by the Forces of Light!  ---PHB

A heavyweight storm, which seemed to stand still Monday night as it hammered Piedmont, shut down a 20-mile stretch of Interstate 90 north of Rapid City, stranding dozens of motorists. 

Up to a foot of water covered the Interstate in some areas, and I-90 was closed for a time between mile markers 32 and 55, according to the South Dakota Highway Patrol.

One motorist spotted cars backed up for miles on I-90. Authorities advised drivers to avoid flooded roadways. 

The brunt of the storm hit Piedmont, where hail up to the size of a softball was reported. A funnel cloud was also spotted near Piedmont, but there were no confirmed tornadoes or damage from the storm, according to Mitchell Erickson, a hydro-meteorological technician with the National Weather Service office in Rapid City. 

Erickson said he expected the storm to taper off as temperatures cooled later in the evening.

Flash flood warnings were issued for southeastern Lawrence County, south central Meade County and central Pennington County. Rain totals in those counties ranged from 2 to 6 inches, and flash flooding was reported along Box Elder Creek. 

"I’m sure there is going to be lots of damage," said Meade County Sheriff Ron Merwin.

Meade County Commissioner Alan Aker said he was concerned about flooding at Exit 46 on I-90. Aker spotted golf-ball-sized hail outside his home in Piedmont, but said the storm "wasn't as bad as the 2005 thunderstorm as far as hail damage."

Steve Hilton, who lives with his family about four miles east of I-90 off Elk Creek Road, said a neighborhood rain gauge measured 1.92 inches.

Pastor Karl Kroger of Grace United Methodist Church in Piedmont was about to leave for a church meeting Monday night but decided to wait when it started hailing. 

“Usually hail is finished in 10 minutes," Kroger said, "but it kept going for over an hour.”

He said the hailstones were "at least golf ball" size. “First it was hail, then rain, and pretty soon rivers all over the town.”

“From a couple of blocks away, you could hear all that water coming down the hills.”

From traffic on the police scanner, it sounded as if I-90 had reopened about 9:30 p.m.

http://rapidcityjournal.com/news/local/flooding-closes-part-of-i--near-rapid-city/article_223e117e-f3cc-598f-b37e-c69b7e25d68a.html?print=true&cid=print