This is an archived article that was published on sltrib.com in 2017, and information in the article may be outdated. It is provided only for personal research purposes and may not be reprinted.
Gov. Gary Herbert has declared the week of March 12 to be Flood Safety Awareness Week. Box Elder County has seen flooding this year already, and the Utah Division of Emergency Management said the state is likely to see more.
At the beginning of March, the Colorado River Basin Forecast Center (CBRFC ) released data that anticipated various parts of Northern Utah would get 200 percent of its average water supply.
But since that forecast, Utah will have experienced ten consecutive days (through Wednesday) without precipitation, a dry spell which meteorologist Randy Graham said Salt Lake City hasn't experienced since mid-November. Those dry days decreased the risk of flooding, but Utahns are still being warned to prepare.
There is still time to melt the snowpack efficiently so it doesn't flood later, said meteorologist Randy Graham.
"If we stay dry and mild, we can have a more orderly snowmelt," Graham said.
The solar radiation is currently melting off the lower snowpack at a rapid rate, which National Weather Service hydrologist Brian McInerney said takes the edge off the flood rate, "but it's still a balancing act."
Ideally, Utah would need cold temperatures and average precipitation until mid-April before starting to dry up, according to McInerney. Then, precipitation would need to slowly decrease, and temperatures would need to gradually rise for the snowpack to melt most efficiently.
But Tuesday was 20-25 degrees above normal temperature, according to data from the CBRFC, which compares daily temperatures to a 30-year average. The center sees a trend toward above-average daily temperatures because the climate is getting warmer, said Graham.
"Every time you melt early, such as in March or even earlier, like we did in February, it becomes very inefficient," said McInerney, who added that water evaporates before it gets to reservoirs and plants come back too early and pull water out of the ground. "You lose a lot to the atmosphere. You can lose up to 50 percent of our water and snowpack if you melt prematurely."
The Federal Emergency Management Agency (FEMA) maps flood-hazard areas to help people identify their risk of flooding, but nationally, 25 percent of flooding is outside of the flood-hazard area, and in areas that are normally considered low-risk, said Kathy Holder, the National Flood Insurance Program coordinator for Utah.
"Any place you have clay, [the ground] will not allow the water to infiltrate, and that was the Bonneville Lake bed," said McInerney. "Those are the soils we see in the valleys around here."
Be Ready Utah encouraged people to prepare for floods by making copies of insurance information, wills, titles and other important documents, said Wade Mathews, the manager of the state's emergency preparedness program. As with preparing for any disaster, document household belongings for insurance purposes, said Mathews.
When flooding starts, Mathews said to disconnect electricity, unplug appliances and shut off water to prevent contamination.
McInerney said future Utahns can expect the flooding scenario to get worse because of increasing temperatures due to climate change.
"Eventually, we'll be in a rain-driven hydrology. We won't have snow in the mountains by roughly [year] 2100. We'll be void of snow. We'll have rain almost all the time," said McInerney.
"If we quit burning fossil fuels and quit putting carbon dioxide in the atmosphere, the warming is expected to be about seven degrees, because the stuff stays in the atmosphere for a thousand years. CO2 stays in the atmosphere for a thousand years; it doesn't precipitate out." said McInerney. "If we were suddenly to reduce our carbon footprint and go to clean energy and we stop putting carbon into the atmosphere, seven degrees is what we expect by 2100."
And if not, McInerney said the expected warming is twelve degrees.
"Twelve degrees is business as usual," said McInerney.