IMET Blog Post: Washington Fire Weather Decision Support

Hey everyone! I’m out here working on the Washington Fire near Markleeville, CA as an Incident Meteorologist, or “IMET” for short. I was dispatched to support an Incident Management Team from the Great Basin that has been assigned to manage the fire suppression efforts for the Washington Fire. As the IMET, I give direct decision support to the Incident Commander and the rest of the wildland firefighters that are working hard to contain this fire.  
Courtesy of Sierra Front Wildfire Cooperators

 One of my primary functions is to keep the firefighters informed on weather conditions that are favorable for suppression efforts such as letting them know about light winds that were going to be favorable for their firefighting efforts earlier this week. With that information, the team was able to put together a plan that was very aggressive for fighting the fire directly with many hand crews and fire engines, taking advantage of the favorable weather.

 On the other extreme, I also let them know when the weather is going to be unfavorable. In this case, we are expecting thunderstorm activity over the fire area Friday, Saturday, and Sunday. Even though there is only a chance that a thunderstorm will affect the fire directly, I still let them know of the potential of thunderstorms and probability that it will impact their operations. These impacts can include increased fire activity, grounding of helicopters and air operations, and most importantly impacts to the personal safety of the firefighters in the field.

 In the next few days, the threat will be lightning, strong outflow winds, the potential for flash flooding and debris flows on the burn scar. So, by telling the fire leadership ahead of time and briefing the crews on the impacts from weather, they are able to plan for and mitigate those impacts.

 An IMET is only one part of the 900 people assigned to fight this fire. Most of the time, our role is a very small piece of the whole operation, but when firefighter and public safety is on the line, we are here to help everyone come home safely!
Reno IMET briefing Nevada Governor Brian Sandoval, U.S. Secretary of the Interior Sally Jewell, and California Secretary for Natural Resources John Laird. The briefing included the weather impacting the fire and how the upcoming weather over the next couple weeks will impact the fire season going forward.

 For updates on the Washington Fire, follow Sierra Front Wildfire Cooperators on Facebook and/or @mindendispatch on Twitter. 

Popular posts from this blog

What is the Rain Shadow and What's Wind Gotta do With It?

Image
The dreaded rain shadow - something that those of us who live east of the Sierra crest are more than familiar with and hate to hear. So what is this rain shadow and why does it even exist? Lets start with the topography just to our west... The Sierra Nevada mountain range runs 400 miles from north-to-south and is approximately 70 miles wide. It includes the highest peak in the lower 48, Mt Whitney at 14,505 feet, and rises above 10,000 feet in many locations. Left: The Sierra Nevada Mountains highlighted in blue. Right: A relief map showing elevation (in meters) of the Sierra. The Sierra are a significant barrier for Pacific storms which typically move from west to east. The movement of air masses and associated weather cannot go through the mountains and is forced up and over the mountain range. As Pacific moisture is driven eastward by the wind, the air mass is lifted up and over the Sierra. Rising air will cool and once it reaches the point of saturation, condense into
Read more

NWS Wind Forecasts: AKA What's the Deal With Friction?

Image
We have had a number of comments on social media which mention much lower observed wind speeds locally than are in the forecast. Well, you are unlikely to know this (it is not exactly advertised!) but National Weather Service wind forecasts are for 10 meters, or almost 33 ft, above the ground. As we are about to explain, that makes all the difference in the wind between eye-level (~5-6 feet) and ~33 feet.  It is natural to wonder the purpose of a wind height forecast well above where you and I typically reside. The main reason for this is the complication in forecasting wind as one nears the ground due to frictional influence caused by the surface. Here is a diagram showing the concept of wind speeds change as one gets away from the ground.  As you can see above, there is a rapid speed reduction (gray dashed line) near the ground with a lesser change away from the surface. Note that the above diagram is generalized. How much reduction is realized depends on the nature of the surface wh
Read more

Forecasting "Dry Microburst" Potential From Soundings and Observations

Image
Summer afternoons in the valleys of eastern California and western Nevada usually feature dry low level relative humidity. In certain cases where low levels are very dry (single digit relative humidities) and enough instability for showers and/or thunderstorms exists, there is the heightened possibility for severe (over 60 mph) outflow winds. Now, severe winds are possible from strong thunderstorms in many cases, even without very dry surface relative humidity. However, what makes very dry surface or low level conditions special is that severe outflow winds are possible even with w eak  convection such as light showers...or even just cumulus clouds! When severe winds are produced by convection with little or no rainfall reaching the ground, it is referred to as a "dry microburst". Microbursts can be of significant danger to aviation and, if they are strong enough, life and property. Before we move onto what conditions we look for to determine the threat for dry microbursts,
Read more