{"id":12444,"date":"2020-07-23T10:49:19","date_gmt":"2020-07-23T16:49:19","guid":{"rendered":"https:\/\/www.coloradofloodthreat.com\/?p=12444"},"modified":"2020-07-24T07:12:04","modified_gmt":"2020-07-24T13:12:04","slug":"spm-07-23-2020-heavy-downpours-over-western-colorado-cause-flash-flooding","status":"publish","type":"post","link":"https:\/\/archive-coftb.dewberryanalytics.com\/?p=12444","title":{"rendered":"SPM 07-23-2020: Heavy Downpours over Western Colorado Cause Flash Flooding"},"content":{"rendered":"<p>Issue Date: Thursday, July 23rd, 2020<br>\nIssue Time: 10:50AM MDT<\/p>\n<h3>Summary:<\/h3>\n<p>A couple storms caused some heavy downpours and minor <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;flash flooding&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;&amp;lt;!-- wp:paragraph {&amp;quot;textColor&amp;quot;:&amp;quot;white&amp;quot;} --&amp;gt;\n&amp;lt;p class=&amp;quot;has-white-color has-text-color&amp;quot;&amp;gt;flash flooding can refer to usually dry areas becoming rapidly inundated with water, or rapid water level rises on streams, creeks, or rivers beyond flood stage; typically caused by heavy rainfall, but can also be caused by meltwater&amp;lt;\/p&amp;gt;\n&amp;lt;!-- \/wp:paragraph --&amp;gt;&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>flash flooding<\/span> over the western part of the state yesterday as moisture moved its way north through the state. A strong thunderstorm impacted the Glenwood Springs area yesterday, which caused muddy runoff to flood local streets and prompted a Flood Advisory by <span class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;NWS&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;National Weather Service&lt;\/div&gt;\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>NWS<\/span> Grand Junction. Two <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;CoCoRaHS&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;&amp;lt;!-- wp:paragraph {&amp;quot;textColor&amp;quot;:&amp;quot;white&amp;quot;} --&amp;gt;\n&amp;lt;p class=&amp;quot;has-white-color has-text-color&amp;quot;&amp;gt;&amp;lt;strong&amp;gt;Co&amp;lt;\/strong&amp;gt;mmunity &amp;lt;strong&amp;gt;Co&amp;lt;\/strong&amp;gt;llaborative &amp;lt;strong&amp;gt;Ra&amp;lt;\/strong&amp;gt;in, &amp;lt;strong&amp;gt;H&amp;lt;\/strong&amp;gt;ail, and &amp;lt;strong&amp;gt;S&amp;lt;\/strong&amp;gt;now Network, a volunteer network of precipitation observers across the country&amp;lt;\/p&amp;gt;\n&amp;lt;!-- \/wp:paragraph --&amp;gt;&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>CoCoRaHS<\/span> rain gauges reported 0.80 inches of rain near town, and one gauge just south of town reported up to 1.16 inches! The <span class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;QPE&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;&amp;lt;strong&amp;gt;Q&amp;lt;\/strong&amp;gt;uantitative &amp;lt;strong&amp;gt;P&amp;lt;\/strong&amp;gt;recipitation &amp;lt;strong&amp;gt;E&amp;lt;\/strong&amp;gt;stimate; an estimate of the amount of precipitation that has fallen at a particular location or across a region based on several different data sources, such as radar or satellite; QPE is often calculated using remotely-sensed data sources&lt;\/div&gt;\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>QPE<\/span> map shows this area of heavy rain just south of Glenwood Springs well, with up to 1 inch estimated. A second area of heavy rain along a south-to-north band over San Miguel and Montrose County in southwestern Colorado prompted a Flood Advisory from <span class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;NWS&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;National Weather Service&lt;\/div&gt;\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>NWS<\/span> Grand Junction due to law enforcement reports of debris on route 145 due to &ldquo;minor runoff.&rdquo; The <span class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;QPE&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;&amp;lt;strong&amp;gt;Q&amp;lt;\/strong&amp;gt;uantitative &amp;lt;strong&amp;gt;P&amp;lt;\/strong&amp;gt;recipitation &amp;lt;strong&amp;gt;E&amp;lt;\/strong&amp;gt;stimate; an estimate of the amount of precipitation that has fallen at a particular location or across a region based on several different data sources, such as radar or satellite; QPE is often calculated using remotely-sensed data sources&lt;\/div&gt;\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>QPE<\/span> map indicates just over 0.5 inches of rain fell over an <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;isolated&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;less than 10% areal coverage&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>isolated<\/span> part of this area just south of the town of Norwood. An ASOS station just northeast of Norwood picked up 0.26 inches of 24-hour rainfall, and a <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;CoCoRaHS&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;&amp;lt;!-- wp:paragraph {&amp;quot;textColor&amp;quot;:&amp;quot;white&amp;quot;} --&amp;gt;\n&amp;lt;p class=&amp;quot;has-white-color has-text-color&amp;quot;&amp;gt;&amp;lt;strong&amp;gt;Co&amp;lt;\/strong&amp;gt;mmunity &amp;lt;strong&amp;gt;Co&amp;lt;\/strong&amp;gt;llaborative &amp;lt;strong&amp;gt;Ra&amp;lt;\/strong&amp;gt;in, &amp;lt;strong&amp;gt;H&amp;lt;\/strong&amp;gt;ail, and &amp;lt;strong&amp;gt;S&amp;lt;\/strong&amp;gt;now Network, a volunteer network of precipitation observers across the country&amp;lt;\/p&amp;gt;\n&amp;lt;!-- \/wp:paragraph --&amp;gt;&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>CoCoRaHS<\/span> report of 0.35 inches came in from the next town southeast (Placerville). A Weather Underground station just north of the town of Norwood picked up 0.76 inch of rain over two hours from 1-3PM MDT as two periods of heavy rain moved over the area. This indicates the <span class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;QPE&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;&amp;lt;strong&amp;gt;Q&amp;lt;\/strong&amp;gt;uantitative &amp;lt;strong&amp;gt;P&amp;lt;\/strong&amp;gt;recipitation &amp;lt;strong&amp;gt;E&amp;lt;\/strong&amp;gt;stimate; an estimate of the amount of precipitation that has fallen at a particular location or across a region based on several different data sources, such as radar or satellite; QPE is often calculated using remotely-sensed data sources&lt;\/div&gt;\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>QPE<\/span> may be underestimating rainfall along the northern portion of this heavy rain band. Other locations across western Colorado also picked up some beneficial rainfall, including reports of 0.43 inch of rain near Pagosa Springs in the San Juan Mountains and 0.38 inch of rain in eastern Moffat County along the Northwest Slope. A few strong wind gusts, up to 53 mph, were also reported over the Grand Valley from thunderstorm <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;outflow&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;A cool pool of air that results when a thunderstorm downdraft reaches the surface and spreads horizontally.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>outflow<\/span>.<\/p>\n<p>Some storms also formed over the Denver area, producing gusty <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;outflow&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;A cool pool of air that results when a thunderstorm downdraft reaches the surface and spreads horizontally.&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>outflow<\/span> winds and up to half an inch of rain over the metro area. A <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;CoCoRaHS&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;&amp;lt;!-- wp:paragraph {&amp;quot;textColor&amp;quot;:&amp;quot;white&amp;quot;} --&amp;gt;\n&amp;lt;p class=&amp;quot;has-white-color has-text-color&amp;quot;&amp;gt;&amp;lt;strong&amp;gt;Co&amp;lt;\/strong&amp;gt;mmunity &amp;lt;strong&amp;gt;Co&amp;lt;\/strong&amp;gt;llaborative &amp;lt;strong&amp;gt;Ra&amp;lt;\/strong&amp;gt;in, &amp;lt;strong&amp;gt;H&amp;lt;\/strong&amp;gt;ail, and &amp;lt;strong&amp;gt;S&amp;lt;\/strong&amp;gt;now Network, a volunteer network of precipitation observers across the country&amp;lt;\/p&amp;gt;\n&amp;lt;!-- \/wp:paragraph --&amp;gt;&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>CoCoRaHS<\/span> report of 0.55 inch of rain was submitted just south of downtown Denver, near Washington Park. An ALERT gage just northeast of the area reported 0.43 inch of rain over an hour. This <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;isolated&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;less than 10% areal coverage&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>isolated<\/span> area was picked up on the <span class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;QPE&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;&amp;lt;strong&amp;gt;Q&amp;lt;\/strong&amp;gt;uantitative &amp;lt;strong&amp;gt;P&amp;lt;\/strong&amp;gt;recipitation &amp;lt;strong&amp;gt;E&amp;lt;\/strong&amp;gt;stimate; an estimate of the amount of precipitation that has fallen at a particular location or across a region based on several different data sources, such as radar or satellite; QPE is often calculated using remotely-sensed data sources&lt;\/div&gt;\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>QPE<\/span> map, which indicated up to 0.5 inch of rain fell, agreeing with observations. Lighter rainfall was observed along the northern Urban Corridor as storms moved north during the afternoon, generally staying below 0.25 inch. The <span class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;QPE&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;&amp;lt;strong&amp;gt;Q&amp;lt;\/strong&amp;gt;uantitative &amp;lt;strong&amp;gt;P&amp;lt;\/strong&amp;gt;recipitation &amp;lt;strong&amp;gt;E&amp;lt;\/strong&amp;gt;stimate; an estimate of the amount of precipitation that has fallen at a particular location or across a region based on several different data sources, such as radar or satellite; QPE is often calculated using remotely-sensed data sources&lt;\/div&gt;\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>QPE<\/span> is indicating an <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;isolated&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;less than 10% areal coverage&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>isolated<\/span> area of heavy rain up to 1.5 inches over eastern Adams County, but the closest rain gauge from a Weather Underground station only reported 0.27 inch of rain. This enhanced <span class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;QPE&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;&amp;lt;strong&amp;gt;Q&amp;lt;\/strong&amp;gt;uantitative &amp;lt;strong&amp;gt;P&amp;lt;\/strong&amp;gt;recipitation &amp;lt;strong&amp;gt;E&amp;lt;\/strong&amp;gt;stimate; an estimate of the amount of precipitation that has fallen at a particular location or across a region based on several different data sources, such as radar or satellite; QPE is often calculated using remotely-sensed data sources&lt;\/div&gt;\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>QPE<\/span> is likely over-estimated. No flooding was reported over the Urban Corridor yesterday.<\/p>\n<p>Thanks to the rainfall over the southeastern portion of the state last week, drought conditions have improved slightly (see image below). Unfortunately, drought conditions also degraded over the northern tier of the state. Hopefully this week&rsquo;s rain over the northeast corner of the state will improve drought conditions for next week&rsquo;s drought monitor update.<\/p>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2020\/07\/20200721_CO_chng_drought.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-12445\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2020\/07\/20200721_CO_chng_drought.png\" alt=\"\" width=\"800\" height=\"618\" srcset=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2020\/07\/20200721_CO_chng_drought.png 3300w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2020\/07\/20200721_CO_chng_drought-300x232.png 300w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2020\/07\/20200721_CO_chng_drought-768x593.png 768w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2020\/07\/20200721_CO_chng_drought-1024x791.png 1024w\" sizes=\"(max-width: 800px) 100vw, 800px\"\/><\/a><\/p>\n<p>For 24-hour to 72-hour rainfall estimates in your area, check out our State Precipitation Map below.<\/p>\n<h4 class=\"collapseomatic \" id=\"id6a1d78d39a495\" tabindex=\"0\" title=\"Click Here For Map Overview\">Click Here For Map Overview<\/h4><div id=\"target-id6a1d78d39a495\" class=\"collapseomatic_content \">\nThe map below shows radar-estimated, rainfall gage-adjusted Quantitative Precipitation Estimates (<span class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;QPE&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;&amp;lt;strong&amp;gt;Q&amp;lt;\/strong&amp;gt;uantitative &amp;lt;strong&amp;gt;P&amp;lt;\/strong&amp;gt;recipitation &amp;lt;strong&amp;gt;E&amp;lt;\/strong&amp;gt;stimate; an estimate of the amount of precipitation that has fallen at a particular location or across a region based on several different data sources, such as radar or satellite; QPE is often calculated using remotely-sensed data sources&lt;\/div&gt;\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>QPE<\/span>) across Colorado. The map is updated daily during the operational season (May 1 &ndash; Sep 30) by 11AM. The following six layers are currently available: 24-hour, 48-hour and 72-hour total precipitation, as well as maximum 1-hour, 2-hour and 6-hour precipitation over the past 24 hour period (to estimate where <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;flash flooding&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;&amp;lt;!-- wp:paragraph {&amp;quot;textColor&amp;quot;:&amp;quot;white&amp;quot;} --&amp;gt;\n&amp;lt;p class=&amp;quot;has-white-color has-text-color&amp;quot;&amp;gt;flash flooding can refer to usually dry areas becoming rapidly inundated with water, or rapid water level rises on streams, creeks, or rivers beyond flood stage; typically caused by heavy rainfall, but can also be caused by meltwater&amp;lt;\/p&amp;gt;\n&amp;lt;!-- \/wp:paragraph --&amp;gt;&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>flash flooding<\/span> may have occurred). The 24-hour, 48-hour and 72-hour total precipitation contain bias corrections that are not disaggregated into the hourly estimates, so there will likely be some differences. The accumulation ending time is 7AM of the date shown in the bottom right corner. Also shown optionally are vulnerable fire burn areas (post 2012), which are updated throughout the season to include new, vulnerable burn areas. The home button in the top left corner resets the map to the original zoom.<br><\/div>\n<p><a href=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2020\/07\/SPM_20200723_snap.png\"><img loading=\"lazy\" class=\"aligncenter wp-image-12458\" src=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2020\/07\/SPM_20200723_snap.png\" alt=\"\" width=\"880\" height=\"616\" srcset=\"https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2020\/07\/SPM_20200723_snap.png 880w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2020\/07\/SPM_20200723_snap-300x210.png 300w, https:\/\/archive-coftb.dewberryanalytics.com\/wp-content\/uploads\/2020\/07\/SPM_20200723_snap-768x538.png 768w\" sizes=\"(max-width: 880px) 100vw, 880px\"\/><\/a><\/p>","protected":false},"excerpt":{"rendered":"<p>Issue Date: Thursday, July 23rd, 2020 Issue Time: 10:50AM MDT Summary: A couple storms caused some heavy downpours and minor <span class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;flash flooding&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;&amp;lt;!-- wp:paragraph {&amp;quot;textColor&amp;quot;:&amp;quot;white&amp;quot;} --&amp;gt;\n&amp;lt;p class=&amp;quot;has-white-color has-text-color&amp;quot;&amp;gt;flash flooding can refer to usually dry areas becoming rapidly inundated with water, or rapid water level rises on streams, creeks, or rivers beyond flood stage; typically caused by heavy rainfall, but can also be caused by meltwater&amp;lt;\/p&amp;gt;\n&amp;lt;!-- \/wp:paragraph --&amp;gt;&lt;\/div&gt;\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'>flash flooding<\/span> over the western part of the state yesterday as moisture moved its way north through the state. A strong thunderstorm impacted the Glenwood Springs area yesterday, which caused muddy runoff to flood local [&hellip;]<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[4],"tags":[],"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/12444"}],"collection":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=12444"}],"version-history":[{"count":2,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/12444\/revisions"}],"predecessor-version":[{"id":12459,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=\/wp\/v2\/posts\/12444\/revisions\/12459"}],"wp:attachment":[{"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=12444"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=12444"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/archive-coftb.dewberryanalytics.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=12444"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}