CA rains: follow-up on January 18th

I am not in a position to provide a detailed follow-up to the post I wrote on January 16th where I wrote about rains continuing on burn scars in California with various Flash Flood Watches being issued by some of the Weather Forecast Office in California. I do know that there was significant rainfall in California as you can see from the map from the NWS California Nevada River Forecast Center (CNRFC) that they posted on their Facebook Page on January 18th.

Here is a map that I obtained from the CNRFC on January 18th. The orange circles indicate River gages that are at monitor stage.

Obtained at 12:08 PM PST on January 18, 2019 from https://www.cnrfc.noaa.gov/

What is monitoring stage? Here is an example of data as of January 18th at 8:13 AM PST from a gage on the Sacramento River at Ord Ferry just southwest of Chico, CA. The gage is located in the Sacramento River National Wildlife Refuge in Butte County, California, go to the link in preceding sentence and scroll down to see a map.

Obtained on January 18, 2019 at 12:34 PM PST from https://www.cnrfc.noaa.gov/graphicalRVF.php?id=ORFC1

The dotted orange link in the above graphic is the bottom of the monitor stage. The data is revised several times a day so what you see if you go the url will be different from what is displayed above.

I do know from reading storm reports from the NWS San Diego whose storm report may be found here ,and the NWS Hanford CA (their storm report is on this website) that there were several reports of flash flooding and debris flows. I do not if there was any property damage from these flash floods and debris flows.  I know from the CBS station in Los Angeles that residents in and near the Holy burn scar in the Lake Elsinore area of Riverside County were under evacuation orders on January 17th, go here to read the article. Mandatory evacuation were downgraded to voluntary orders yesterday. I believe that the voluntary evacuation orders were lifted later on January 17th.

October 1st: Hurricane Rosa, heavy rains and burn scars

Many of you probably heard about the remnants of Hurricane Rosa (the last advisory from the NHC for Rosa was issued on October 2nd) impacting areas of the southwestern United States earlier this week. I have been aware of the risk of debris flows and flash flooding on burn scars in mountainous areas with steep slopes. See for example, see this presentation by the National Weather Service Weather Forecast Office Los Angeles about the January 9, 2018 debris flows on the Montecito CA burn scar.

I am just learning that the risks posed by heavy rains causing debris flows and flash flooding are not just limited to California. While California is known for debris flows on burn scars, other areas of the west with step mountainous terrain are also susceptible. See this short article about why burn scars are susceptible to flash flooding/debris flows from the National Weather Service Western Region Headquarters.

Knowing that Hurricane Rosa impacted areas of the southwestern United States with heavy rains, I looked at a couple of National Weather Service (NWS) Weather Forecast Offices (WFO)  that appeared to impacted by flash flooding from Rosa to see what is and was going on: NWS WFO Salt Lake City Utah and NWS WFO Grand Junction Colorado. Both WFOs had issued flash flood watches with wording about the possibility of debris flows and flash flooding on recent burn scars, I noted graphics on flash flood watches on the Facebook page for both offices.

• The NWS WFO Grand Junction Colorado shared a graphic about a flash flood watch on their Facebook page on October 1st, with wording about the possibility of debris flows/flash flooding on burn scars.
• The NWS WFO Salt Lake City Utah posted a flash flood watch on their Facebook page on September 30th with wording about the possibility of debris flows/flash flooding on burn scars. Some of you might be interested in a briefing from the WFO Salt Lake City Utah on Facebook on October 2nd around mid-day. Please note that the briefing is for a certain point in time and will not reflect conditions that happened after the briefing. 

I don't know if the rains led to debris flows/flash flooding from burn scars in either the Grand Junction or the Salt Lake City WFO. I have not heard about any debris flows/flash flooding on burn scars, but it is entirely possible that I don't have current information. The point here is that it is important that these WFOs were watching for the possibility of debris flows/flash flooding on burn scars in their forecast area so that their citizens could be prepared to take action.

2018 wildfire season: 416 fire (Durango CO)

As I was preparing to write today's blog article, I knew that I wanted to share a crew video that highlights the work of a hotshot crew that worked the 416 fire. I'll share that video below, but first a little about the 416 fire. The 416 fire started on June 1, 2018 about 10 miles north of Durango, CO. the fire was contained on or about July 31st but at the time the interior of the fire was still smoldering. The fire burned 54,129 acres. As I understand there is yet no official cause of the fire, that report will be released sometime late this year. For more information about the containment of this fire read this July 31st Durango Herald Article. The Inciweb page on the 416 fire is still up as I write this, I am not sure how long the page will be accessible. Bill Gabbert of Wildfire Today wrote a few articles on the 416 fire, including references to other wildfires, that burned in Colorado this past summer, go here (416 tag) for those articles. Finally while the 416 fire may be contained, there remains danger from debris flows and flash flooding to the area and area surrounding the 416 fire burn scar.  There has been at least one round of heavy rains that lead to mudslides in and near the area burned by the 416 fire, you may read about it hear in a July 17th Denver Post article.


Direct link to video uploaded by Hank Blum