New runoff created the clog that caused Salt Lake City flooding

A clogged flood control structure caused Wednesday's flooding along Emigration Creek — but the passage was clear just hours earlier, Salt Lake City officials said.

What happened: Tuesday's high temperatures melted the record snowpack in the lower elevations of the mountains, flushing detritus into the swelling creeks that flow into Salt Lake, said Laura Briefer, the city's public utilities director.

• By early Wednesday, debris in Emigration Creek blocked a passage through a flood control structure near Wasatch Hollow, causing the creek to fill the park and spill onto 1700 South that night.

Yes, but: Crews checked the drainage Tuesday night and found the creek was flowing freely mere hours before the blockage developed, Briefer told Axios.

Why it matters: Critics of Mayor Erin Mendenhall took to social media on Thursday to blame the city for not preemptively clearing the waterways.

• In fact, the increased runoff caused a new blockage, Briefer said. Crews won't be able to clear it again until the flows diminish.
• Municipal and county crews have been clearing drains and culverts statewide to prepare for anticipated snowmelt, Gov. Spencer Cox said in a news conference Thursday.

What's next: With temperatures expected to stay low for the coming week, snowmelt should be more controlled and creek flows are expected to remain manageable — for now.

• Most of the snow at the lower and mid-elevations in Emigration Canyon has already melted, Briefer said.
• But as May approaches, temperatures could rise sharply and melt snow high in the mountains, where it's deepest, she added. That could cause creek beds to spill over even if they remain totally clear.

Get smart: Homeowners can look at insurance maps to see where the highest flooding risks exist — but Wednesday brought floods to some areas that aren't marked as a floodplain, Briefer acknowledged.

• Residents should also watch stream flow and weather forecasts, linked on Salt Lake County's spring flooding website, and follow emergency managers on social media for updates, she added.
• Even if you don't live in a marked floodplain, consider protecting your home with sandbags if your building has a history of flooding or if you live near any waterway, including those that run underground, Briefer said.