On Friday, July 3, the National Weather Service was issuing thunderstorm warnings for central Wyoming as Casper prepared for the July 4 celebrations.

But nothing could prepare for the thunderstorm just east of the airport that didn't circulate the moist air but instead quickly drove it down in what the Weather Service technically referred to as a "wet microburst."

The following hours and days underscored issues with Casper's storm water sewer system, which remains a problem today.

The wet microburst innundated areas of the county with up to 1.5 inches of rain in 40 minutes, and its intensity reduced visibility to a few yards. Area wind speeds were clocked at between 47 mph and 65 mph.

The sudden aftermath shocked the city's storm sewer system:

  • On North Lincoln Street, the water pressure blew a sewer lid 15 feet into the air followed by an encore of a four-foot geyser.
  • Streets turned into irrigation channels sending more than a foot of water to East Yellowstone Highway.
  • A law enforcement officer begged onlookers to not wade into the lake under the North McKinley Street underpass.
  • The force of the water flowing down the ramp at the Hall of Justice bent the basement garage door.
  • Cars floated along C Street.
  • People cruised the streets in boats.
  • The Wyoming Department of Transportation closed Interstate 25 between Casper and Glenrock.
  • The rushing water picked up rocks and other debris and deposited them in the streets and on the sidewalks.
  • Many residents reported flood damage to their homes.

Then the bills came.

Former (and now) Mayor Kenyne Humphrey and former Natrona County Commission Chairman Rob Hendry estimated the initial public and private storm damage at $2 million each for the city and county. County damage included $350,000 to the Wyoming Medical Center. The Nicolaysen Art Museum had just replaced its roof, so the damage there was about $30,000 instead of $500,000.

In 2013, the City of Casper commissioned a study of the aging storm sewer system.

Tuesday, Tom Bauer of Civil Engineering Professionals, LLC, told the city council at a work session that the city will need to spend $46 million for 42 major projects in the next 20 years to upgrade the system.

Without those improvements, and a method to pay for them, Casper may relive July 3, 2009, again, Brauer said.