Observation: These images were posted to the Facebook page 'My Home is Alaska' by Mark Stursy and images taken by Kyle Iring. With their permission to share, I thought this is a unique image of a funnel cloud not to far from where I live, and a rare event in Alaska!
LEO says: Funnel clouds are of particular interest in Alaska because of thhey are so rarely sighted or at least reported. There are several different types of funnel cloud formations that occur in Alaska.
In 2016, researchers from the University of Alaska Fairbanks, University of Colorado at Boulder, and the National Weather Service Forecast Office, came together to better understand the characteristics of Alaskan funnel clouds, and improve forecasting ability around the state.
Examining funnel cloud events in the interior, west coast, and Anchorage regions of Alaska, researchers found that some types of funnel clouds occurred under weak synoptic (large) scale forcing throughout the troposphere (the lowest region of the atmosphere).
These funnel clouds were found to be non-supercell thunderstorm clouds, meaning that the clouds form from air that is already spinning vertically near the ground, from wind shear from a warm, cold, or sea breeze front, or a dryline. The funnel shape forms when an updraft moves over the spinning air, and stretches it. The specific weather conditions associated with funnel cloud formation in Alaska vary by region, but researchers believe that these can be identified from surface observations, mid- and upper-level synoptic maps, and radiosonde profiles.
Source: "Conditions Supporting Funnel Cloud Development in Alaska" by Stanley G. Edwin, Nicole Mölders, Katja Friedrich, Sebastian Schmidt, Richard Thoman.
National Weather Service Alaska Region Consult: Rick Thoman, Climate Science and Services Manager, writes, "This photo is a nice example of a well developed "cold air funnel". Cold air funnels are only distant cousins of the monster storms of the Midwest. These cold air funnel clouds form in the middle levels of the atmosphere, typically when the air is cooling rapidly with height and there is a well defined increase in wind speed and/or change in direction. Unlike the big tornadoes of the Midwest, cold air funnels usually don't occur in association with thunderstorms. On the day this occurred, the BLM's lightning detection network did not record any lightning strikes in the Susitna Valley. Because they form well above the ground, they rarely touch down and don't tend to last very long. Cold air funnels have been spotted before in Alaska, and are probably more common than generally realized, but thanks to the LEO Network we are learning more about their occurrence." National Oceanic and Atmospheric Administration (NOAA)
Resources:
National Severe Storms Laboratory – The NOAA National Severe Storms Laboratory provides information on severe weather, including tornadoes. This article distinguished the difference between supercell thunderstorms and non-superstorms, as referenced above. Check out Types of Tornadoes. National Oceanic and Atmospheric Administration (NOAA)
