Yes, Des Moines has been really foggy in January — a record-setting amount of fog.
Nine dense fog advisories have been issued in January. That’s a new record for the month of January, topping the eight advisories issued in January 2017.
What is a dense fog advisory?
A dense fog advisory means widespread visibility reductions of a quarter of a mile or less are expected or occurring, according to the National Weather Service. Drivers are encouraged to exercise caution in the advisory area.
In 2023, the NWS office in Des Moines issued 19 fog advisories. While it’s not an all-time high, it beats out 2022’s 12 advisories and the 14 issued in 2021.
More: Des Moines’ temperatures had a 73-degree swing in January. See the highs and the lows.
Why is it so foggy in Des Moines right now?
In short? Because it snowed so much early in January.
“There are multiple factors that can lead to dense fog formation, but recently the primary driver has been the long, slow melting of the deep snowpack we had from the storms earlier this month,” said Jim Lee, a National Weather Service meteorologist. “That introduced a lot of water vapor into the near-surface layer of the atmosphere, which was then trapped by a persistent temperature inversion aloft, and supported by generally light winds.”