EPOW - Ecology Picture of the Week

Downburst and Jackstraw

Thunderstorm Downburst
Ger Camp, Gobi Desert, Mongolia

Explanation:  Have you ever been caught in a thunderstorm downburst?  According to the U.S. National Weather Service, "downbursts are powerful winds that descend from a thunderstorm and spread out quickly once they hit the ground."  They can be as severe as a low-grade tornado, although they are a different phenomenon.  In the main photo, above, I once caught a downburst pummeling an isolated part of the Gobi Desert in southern Mongolia.  Luckily it did not hit our ger campsite, in the foreground.

Downbursts -- also known as microbursts if they are 2.5-miles in diameter or less -- can cause devastating damage to structures and to natural environments as well.  Here is an example of the likely result of a downburst in a previously fire-ravaged black spruce boreal forest in central Alaska:

In the background in the above photo, you can see how a major wildfire had killed
a massive area of black spruce (Picea mariana) forest.  And then, in this confined area, a likely
downburst leveled the trees all lying now in the same direction. 
  
In a previously EPOW episode, we encountered a similar situation in a temperate
conifer forest in Oregon, USA.  But here, in Alaska, I was surprised to
see such a similar situation, resulting in a chaotic jackstraw deposit of downed trees.

  
Is this really "devastation?"  Consider that down wood in the forest plays very
important ecological roles as habitat for wide variety of plant and animal species,
and contributes nutrients to the soil over time.  And, as we saw in that previous
EPOW episode, it can help open up the forest canopy to let in light that
provides germination and growth of forest floor vegetation.
 
So, in some ways, the fury of a downburst can provide some useful,
valuable ecological conditions.  But just seek shelter, should the
warning come your way!

 

And here is an example of how a major downburst can be swept horizontally as it reaches ground level.

I caught this example during a work trip to Pabitora Wildlife Sanctuary in Assam, India.

Luckily, we distant enough to not feel its main effects.