{"id":68186,"date":"2025-12-17T23:59:00","date_gmt":"2025-12-17T23:59:00","guid":{"rendered":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/?p=68186"},"modified":"2025-12-19T18:04:39","modified_gmt":"2025-12-19T18:04:39","slug":"downslope-high-wind-event-across-the-colorado-foothills-and-a-wind-driven-grass-fire-in-eastern-colorado-prompting-evacuations","status":"publish","type":"post","link":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/68186","title":{"rendered":"Downslope high wind event across the Colorado Foothills, and a wind-driven grass fire in eastern Colorado prompting evacuations"},"content":{"rendered":"

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1-minute GOES-19 Water Vapor images, from 1801 UTC on 17 December to 0021 UTC on 18 December [click to play MP4 animation]<\/p><\/div>1-minute Mesoscale Domain Sector GOES-19 (GOES-East)<\/em>\u00a0Water Vapor images (above)<\/em><\/strong> displayed an intermittent signature of subsidence-induced warming\/drying (brighter shades of yellow to orange) that led to the development of strong downslope winds in the Front Range of Colorado on 17 December 2025<\/strong><\/a>. Several sites recorded peak wind gusts in excess of 100 mph<\/strong><\/a>.<\/p>\n

A toggle between a GOES-19 Water Vapor image and Topography (below)<\/em><\/strong>\u00a0showed the signature of subsidence just downwind (east) of the higher elevation of Colorado’s Rocky Mountains.<\/p>\n

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GOES-19 Water Vapor image at 2242 UTC + Topography [click to enlarge]<\/p><\/div>GOES-19 Visible images (below)<\/strong><\/em> highlighted gaps in patches of dense clouds that allowed the subsidence signatures to be seen in Water Vapor imagery.<\/p>\n

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GOES-19 Visible images, from 1801-2300 UTC on 17 December [click to play MP4 animation]<\/p><\/div>\n

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Several hours after sunset, GOES-19 Shortwave Infrared images (below)<\/strong><\/em> showed the thermal signature associated with a wind-driven grass fire in Yuma County (located in far eastern Colorado) — which prompted the issuance of a Fire Warning<\/strong><\/a> that led to evacuations. About and hour prior to the onset of the fire, there was a wind gust to 77 kts (88.6 mph)<\/strong><\/a> to the west of Yuma County at Akron — and shortly after the fire began, there was a wind gust to 80 mph<\/strong><\/a> at a RAWS site in southeastern Yuma County.<\/p>\n

The initial fire detection in GOES-19 Shortwave Infrared imagery appeared to be at 0507 UTC<\/strong><\/a> — but until that time, there was a layer of dense cloud cover moving across the area (which masked the view of the surface, so the fire could have started earlier).<\/p>\n

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1-minute GOES-19 Shortwave Infrared images, from 0401-0900 UTC on 18 December [click to play MP4 animation]<\/p><\/div>The thermal signature of this Yuma County, Colorado grass fire was also very apparent using the Next Generation Fire System<\/strong><\/a> (below)<\/strong><\/em>. As with GOES-19 Shortwave Infrared imagery, the initial NGFS detection for this fire also occurred at 0507 UTC<\/strong><\/a>.<\/p>\n

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1-minute GOES-19 Microphysics RGB images with an overlay of NGFS Fire Detection polygons, from 0430-0900 UTC on 18 December [click to play MP4 animation]<\/p><\/div>\n","protected":false},"excerpt":{"rendered":"

1-minute Mesoscale Domain Sector GOES-19 (GOES-East)\u00a0Water Vapor images (above) displayed an intermittent signature of subsidence-induced warming\/drying (brighter shades of yellow to orange) that led to the development of strong downslope winds in the Front Range of Colorado on 17 December 2025. Several sites recorded peak wind gusts in excess of 100 mph. A toggle between […]<\/p>\n","protected":false},"author":18,"featured_media":68189,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[6,159,158],"tags":[],"class_list":["post-68186","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-fire-detection","category-goes-19","category-ngfs"],"acf":[],"_links":{"self":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/68186","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/users\/18"}],"replies":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/comments?post=68186"}],"version-history":[{"count":22,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/68186\/revisions"}],"predecessor-version":[{"id":68210,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/68186\/revisions\/68210"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media\/68189"}],"wp:attachment":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media?parent=68186"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/categories?post=68186"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/tags?post=68186"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}