EF2 Tornado — Teton, Wyoming

2022-06-12 · near Kelly, Teton, Wyoming

Event narrative

Several months after this event, Bridger Teton National Forest staff reached out to the NWS Riverton office and shared images and helicopter footage of a distinct path of tree damage through a thickly-forested high-elevation area that coincided with a supercell path from June 12, 2022. This area of widespread tree damage was inaccessible and not viewable to the NWS damage survey team that visited the valley nearby immediately following the event.

Post-event interrogation of radar imagery from the event shows a strong rotation couplet above this damage area. After consulting with other Great Plains NWS staff with more than 20 years of tornado-damage-determining experience, this was determined to be tornado damage. The tree fall pattern and path were consistent with strong tornadic rotation.

The EF2 designation comes from looking at the softwood damage indicator of the Enhanced Fujita Scale. Pictures show thousands of pine trees snapped at various heights, with hardly any trees remaining upright. There was some evidence of debarking in photos as well. For this reason, wind speeds were estimated to be between 128 and 131 mph, based on the upper bound for softwood trunks snapped and the expected damage for softwood debarked.

Path length and width were determined from polar-orbiting satellite data from the summer months after the event. Notable decreases in vegetation could be seen, with a clearly defined damage path.

Wider weather episode

In a warm and unstable air to the south of a stationary front, several supercell thunderstorms developed. The storms brought large hail, in addition to strong winds that toppled many trees across western Wyoming.

View location on OpenStreetMap → (43.5884, -110.5228)

Source: NOAA Storm Events Database, event_id 1064764. Narrative written by the NWS forecast office that issued the report.