Utah flooding updates: Nebo Loop road washes out; Big Cottonwood Creek flood risk eases

Officials are keeping an eye on the Provo, Ogden and Sevier rivers.

(Uinta-Wasatch-Cache National Forest) Spring runoff has washed away a section of the Nebo Loop Scenic Byway, which typically opens on Memorial Day weekend. The roadway will remain closed as repairs are made, which could take about two weeks, officials said.

Editor’s note • The Salt Lake Tribune is providing free access to this vital story about flooding. Sign up for our Top Stories newsletter, sent to your inbox every morning. To support journalism like this, please donate or become a subscriber.

Utahns who are accustomed to driving the popular Nebo Loop Scenic Byway on Memorial Day weekend are going to have to wait this year — a section of the road has collapsed because of flooding, creating a waterfall.

According to officials with the Uinta-Wasatch-Cache National Forest, the damage occurred as water flowed across the roadway just below the turnoff for the Pete Winward Reservoir, about 9 miles up Payson Canyon. There’s no estimate of when the road will be repaired, but it’s expected to be about two weeks before it can reopen.

Elsewhere in the national forest, the Monks Hollow Trail near Mapleton is closed until further notice because it has washed out in several areas. There’s no estimate of when it will be repaired.

(Uinta-Wasatch-Cache National Forest) The Monks Hollow Trail near Mapleton is closed until further notice because it has washed out in several areas.

The Mount Timpanogos Campground — which was scheduled to open this past Saturday, remains closed because there is 2-3 feet of snow on the ground there. Officials have no estimate for when the campground will open.

Though the Little Mill Campground is open, there are two logjams nearby that are “affecting a few campsites” and the trail that leads to the Sawmill Day Use area, according to Uinta-Wasatch-Cache officials.

Provo River

Provo City officials have warned residents to stay away from the Provo River, which will see a “substantial increase in flows” over the next few weeks as more water is released from Deer Creek Dam.

“The high flows will be extremely dangerous, cold, and swift,” according to the city. “Please maintain a safe distance and keep children and pets away from the water.”

The city also advised that the river water “carries lots of debris, bacteria and animal waste,” and noted that it only takes about 6 inches of water to knock someone off their feet.

Big and Little Cottonwood Creeks

(Francisco Kjolseth | The Salt Lake Tribune) Swift currents surge through Big Cottonwood Creek on Tuesday, May 16, 2023.

Although forecasts predicted Big Cottonwood Creek would experience minor flooding this week, cloud cover has helped slow down much of the area’s snowmelt, said Brian McInerney, a hydrologist who consults with Salt Lake City on flooding.

Over the next few days, the highest rate that Big Cottonwood Creek is expected to flow is about 621 cubic feet per second, according to the National Weather Service. That rate will surpass the creek’s “action stage” of about 600 cfs, which is a threshold that the weather service uses to determine when it should take action to prepare for possible flooding.

The creek’s threshold for minor flooding is at about 798 cfs, according to the service.

Little Cottonwood Creek’s peak flow expected over the next few days is 660 cfs. This creek’s threshold for minor flooding is about 799 cfs, according to the service.

“The weather is just about perfect,” McInerney said. “We’ve had high flows, a lot of a little streams and drainages are running high but nothing that’s causing much damage. And that’s due primarily to how the weather’s shaping the runoff.”

McInerney now expects peak flows for Big and Little Cottonwood creeks to occur in early to mid-June.

“We’re feeling much less anxious over this,” he said.

South fork of the Ogden River

The river is above the flood stage near Huntsville, and is expected to remain there through Sunday, according to the National Weather Service.

Because of spring snowmelt runoff, low-lying areas near the banks below the Causey Reservoir through the town of Huntsville will experience “minor flooding.”

Sevier River

The river is expected to fluctuate just above moderate flood stage near Hatch through late this week, according to the weather service, and fall to minor flood stage by the weekend.

Moderate flooding will affect fields, roads and bridges in low-lying areas, including the river crossing on South Hatch Dam Road.