Nevada I-15 flooding required a multi-state response

A two-mile stretch of I-15 near milepost 91 in Nevada was washed away due to heavy rainfall that started on Monday, September 8th. In an unprecedented storm around 4 inches of rain fell in the space of 2 hours, flooding the road and washing away ground and asphalt leaving the interstate impassable. Record breaking numbers of rainfall were reported along streams in the area.

The Nevada DOT declared a state of emergency on Tuesday, September 9 due to the importance of passenger vehicle and commercial trucking flow on I-15. According to Arizona Department of Transportation, approximately 23,000 vehicles use I-15 each day between St. George, Utah and Las Vegas, Nevada.

Warnings on Utah’s freeway message boards were posted up and down I-15 letting drivers know that the freeway would be closed down and provided details for  alternate routes. These signs went as far east as Nebraska to provide enough time for travelers to change their routes.

Screen shot of tweet that says 'From nevadadot semi restriction lifted (except oversie w/o permit) on NV I-15Information was also available to drivers via the 511 phone line, the Utah Trucking Association, news outlets, Arizona and Nevada DOT’s, the UDOT Traffic website, the UDOT Traffic Twitter account and the UDOT Traffic app. UDOT’s social media channels proved very valuable during this event.

Travelers were directed to take S.R. 56 out of Cedar City to Nevada S.R. 319 and then to the U.S. 93 back to the freeway. UDOT and NDOT worked very hard to provide accurate and timely information to motorists traveling on this alternative.

State DOT’s had to work together. Although the closure was not in Utah UDOT was heavily involved in sending support to the affected areas. Due to increased traffic on S.R. 56 a UDOT Incident Management Team (IMT) was dispatched to assist. The IMT crews directed traffic, filled potholes and moved disabled semis out of traffic.

They also deployed a portable traffic camera trailer to the S.R. 18/S.R. 56 junction to monitor any potential problems and back-ups. UDOT’s Region 4 shared access to this camera with Nevada DOT. Region 4 was also able to respond quickly to a rockslide on the Arizona section of I-15 and sent snow plows to clear rock debris in the Virgin River Gorge area.

Southbound I-15 reopened to traffic on Friday, September 12th to one lane in each direction for passenger vehicles. Northbound lanes reopened on September 18.

Glenn Blackwelder a Traffic Operations Engineer at UDOT said “We could not have done it on our own. It took the communication and resources of the Traffic Operations Center, Region 4 and NDOT working together. We were pleased with how all agencies and divisions were able to work together to get I-15 back open as quickly as possible.”Screen shot of tweet and attached map showing detour route. The tweet reads "Reminder: Nevada I-15 closed due to flooding. So Cal and Vegas detour map:"

This guest post was written by Adam McMillan, Traffic Operations Center Intern.

Leave a Comment

Your email address will not be published. Required fields are marked *