High country flooding possible this week
FLAGSTAFF — After receiving more than 100 inches of snow since the start of the year, Flagstaff may finally receive a break from winter weather with stretches of warmer temperatures finally in the forecast.
“We’re not looking at any impactful storm to really increase our seasonal snowfall for the foreseeable future,” said National Weather Service meteorologist Benji Johnson.
Instead, most of the state can expect to see a rise in temperatures through the weekend, he said. And while there are still higher chances for precipitation in many areas, the higher temperatures mean any moisture outside of the highest elevations will most likely come in the form of rain.
In combination with this potential rainfall, warmer temperatures and higher dew points will speed up snow melt across the high country.
Localized flooding from snowmelt runoff has already begun in some places. A weeklong flood warning was issued for residents in the Tonto Basin on Monday morning as snowmelt continued to increase flows in Tonto Creek.
“We’ve already seen some impacts with water crossings becoming impassable,” Johnson said.
In addition to Tonto Creek, he said, all of the drainages for the Mogollon Rim could see increased flows beginning by this Friday. This includes Wet Beaver Creek, West Clear Creek, Dry Beaver Creek, Tonto Creek, the Verde River, Sycamore Creek, Oak Creek and the Agua Fria River.
Ponding on roadways is also possible, he said, and is even more likely if snow or ice is interfering with drainage systems.
“Any and all of this moisture is helpful because not only do we increase the flows in the local waterways and that goes to local reservoirs,” Johnson said. “But groundwater recharge is an important aspect of spring snowmelt and any precipitation, really.”
Compared to the very intense but short thunderstorms the area sees during monsoon season, winter’s less intense but longer weather events make better conditions for groundwater recharge, he said. Instead of fast-moving rainwater that quickly makes its way down the mountain and through town in the summer, sitting snow has the opportunity to actually melt and be absorbed back into the ground.
Johnson said, a particularly active winter doesn’t offer any clear hints for what Flagstaff could expect moving into wildfire season and then followed by the monsoon. Instead, like usual, residents will just have to wait and see.