On Monday, Salt Lake City Mayor Mendenhall showed off two huge debris basins to make a point about the city’s flood preparedness. From the basins, long-arm tractors can haul out fallen trees, large boulders and other debris to clear obstructed waterways and mitigate flooding. They were installed after the great Salt Lake City flood of 1983, when Utah’s snowfall looked much like it does now. It goes to show, the Mayor says, that without a doubt Salt Lake City is much better prepared for this year’s record snowfall than it was in 1983. The flood risk extends further than Salt Lake County, of course—the Governor declared April as “Flood Safety Month” to encourage all Utahns to be prepared for flooding and other natural disasters—but why is Utah flooding on the top of mind?
Utah flooding causes
To start, we’ve had record snowfall. By late March, the 2022–23 winter season was breaking records on a few levels. Brighton crossed over the 700-inch mark of annual snowfall for the season—a “once in a decade event.” According to Ski Utah, this is the earliest in the season that this has occurred since Utah began recording snowfall in 1943. By April, Alta Ski Area hit the 800-inch inch mark. As of Monday, Alta’s year-to-date snowfall was 877 inches.
This winter is breaking records for snowpack as well. The previous record of 26 inches of snow water equivalent (SWE)—which estimates the amount of water it would be if it melted—was set in 1983. At last check, we are sitting at 29.6 inches, according to the Utah Division of Water Resources.
Utah gets approximately 95% of our water from snowpack. Reservoirs store the water from snowpack and runoff to get us through dry years. And we have had a lot of dry years. The American West is experiencing the worst drought in 1,200 years. That extended drought has depleted reservoirs and, along with human water usage, lowered the Great Salt Lake’s water to precariously low levels. While the record-breaking amounts of snow will help recharge reservoirs and restore the Great Salt Lake, it will take multiple years of above-average snowpack and precipitation to reverse the impact of drought.
One thing that won’t take much time at all, after all of this snow, is flooding from the subsequent spring runoff. Temperatures reached 70 degrees in Salt Lake County on Monday, with temperatures of 10 degrees higher than the seasonal average in the forecast for much of Utah, according to the Salt Lake City National Weather Service. Utah flooding happens when conditions (like unseasonably high temperatures) lead to rapid snow melt and rivers, streams and other water channels become overwhelmed.
Infrastructure improvements since 1983
During the 1983 spring runoff, the storm drain carrying City Creek flows in North Temple became clogged with debris that extended four city blocks. Since then, there’s been the addition of debris basins along City Creek so crews can remove debris before it becomes a problem.
“We’ve made significant infrastructure investments since the floods of 1983 that make us more prepared this time around. We know this is a big concern for our residents and we’re taking it seriously in our planning and preparation,” Mayor Mendenhall says. “From a robust storm water system, to debris basins and the addition of Little Dell reservoir, Salt Lake City and our flood control partners, including Salt Lake County, have been preparing for decades to ensure the best possible outcomes for our residents in high snowpack years.”
Other system improvements include grate improvements in Memory Grove to prevent potential backups, piped drainage system improvements to allow for better conveyance of spring runoff and Little Dell Reservoir (constructed between 1987 and 1993) as a flood control and water storage facility.
Flood preparedness
Flood zone risk mapping
While we can’t know with 100% certainty when and where flooding will occur, FEMA maps areas to show their potential risk for flooding. You can go to the FEMA Flood Map Service Center and enter your address to show the possible risk of flooding in your area.
Sandbags
Salt Lake County representatives say they have been receiving a lot of questions about where to get sandbags. Residents can fill and pick up free sandbags at locations listed on their website: Salt Lake County sandbag locations. The county says that some locations will be checking IDs to verify residency.
Utah flooding risk mitigation
There are a lot of things residents can do to prepare their homes and mitigate flooding and flood damage. However, many of those things take time to build, retrofit or install. As far as what you can do now to prepare:
- Clear gutters and drains of any blockages or debris and keep debris away from steams.
- Sign-up for, if necessary, and keep up-to-date on disaster warnings, local emergency alerts and information. Most communities have an emergency alert system (through cell phone, email or landline) that you can opt into, such as Salt Lake City Emergency Management. FEMA’s Wireless Emergency Alerts are location-based and do not require a subscription.
- Make a plan for your household, including your pets, so that you and your family know what to do, where to go, and what you will need to protect yourselves from flooding.
- Learn and practice evacuation routes, shelter plans and flash flood response.
- Gather supplies, including non-perishable foods, cleaning supplies and water for several days, in case you must leave immediately or if services are cut off in your area.
- If you’re a Utah State employee, Governor Cox announced that he approved eight hours of administrative leave for all Utah State employees to assist with flood mitigation.
- In general, keep clear of spring runoff. Many county parks and trails are designed to be detention basins, so don’t be alarmed if you see more water than usual. Runoff can move suddenly so don’t drive or wade through it and keep kids and pets out of the water.
- Additional flood information is available at beready.utah.gov and floodfacts.utah.gov.
Looking to help?
Salt Lake County Emergency Management has a form that allows people to register to volunteer. SLCoEM uses the list of registrants to connect volunteers with events where the help is needed. When an event arises, they will email information to the volunteers who most closely meet the need.
Southern Utah Flooding
It bears mentioning that some of our favorite outdoor recreational spots have a higher risk for flash flooding during spring runoff. Already, in Kane County, at Buckskin Gulch, flash flooding killed two hikers in the narrow canyon back in March. What draws hikers to Buckskin Gulch—winding through 16 miles through one of the longest slot canyons in the world—is also what makes it particularly dangerous during a flash flood.
A few days later, Washington County Search and Rescue rescued six people, including three children, from Johnson Canyon Trail who had become stranded on the far side of a wash after a flash flood turned that wash into a full-blown raging river.
On the bright side, the the spring runoff has given life to the Dirty Devil for river runners and returned waterfalls (and the crowds) to Gunlock State Park.
