Resources

Wednesday, July 7, 2021

We remain dry but rains have helped

We've recently seen a bit of precipitation across the state, generally ranging from 0.5 - 1.5" over the past 7 days. This has obviously helped the cause as we have been so incredibly dry over the past few months, especially over eastern and central SD. 

But if we look at the 30-day percent of average precipitation, you can see that the conditions remains very dry relative to historical norms. 
We have also been seeing some hot temperatures over the past month which further dries the soils and the fuels on the landscape. Temperatures over the past 30 days have been from 3-7 degrees above average--pretty incredible over the period of a month. 
The vegetation is really becoming drought-stressed due to the combination of heat and little precipitation. The VegDRI product shows this. Top chart is from a month ago, bottom chart is from this week. The situation is getting worse quickly. 

Ok, so things look pretty bad. Has the recent rain helped at all? In short, yes. The rain has at least dampened the fuels so that they are not as receptive to ignitions or to carrying fire. This is especially true for the 1- to 10-hr fuels (needles and grass up to finger-sized sticks). The recent trends in Energy Release Components (ERCs) have demonstrated this. I've shown Baker Park RAWS and Red Canyon RAWS as examples. Whereas they were near or at record highs a few weeks ago, the ERCs are now trending lower than average. But remember, these stations are in the Black Hills which HAVE been getting decent rains--the prairies haven't been getting those same rains. 

So, at least in the Black Hills, conditions are in a holding pattern. We've gotten enough rain to limited the fire threat in the near term. But the prairies are made almost exclusively of fine fuels or those 1-hr fuels. These fuels only take a day or two to fully dry and be conducive to carrying fire. In short, they respond more to the day-to-day weather conditions. If we get a hot/dry/windy day, they will be ready to burn. 

What scares me is the forecast going out towards the latter half of July. There are some strong hints that more hot weather and above average temperatures are on the way. Here are the CPC forecasts from the 8-14 day timeframe and the 3-4 week timeframe. 
That's a tough outlook for the latter half of the month. There is *high* confidence of these warm and dry conditions as well. 

I'm no plant phenology expert, but from my understanding the herbaceous fuels on the landscape really can't pick up and use the moisture that we've gotten over the past week. They've already crossed the threshold: they are seeded out and curing for the season. So the precipitation really won't help them out too much. Add some heat and additional dry weather and it creates a situation where the fire potential will likely increase going into August. 

The big fire out by Pickstown over the 4th of July weekend goes to show that the fuels in the Missouri River breaks will readily carry fire. The eastern red cedar had no problem torching out. Remember that big fires are not limited to the Black Hills here in SD--we have a lot of fuel on the landscape and this might be the year where it burns. 















No comments:

Post a Comment