weathercarrot
12-11-2003, 14:20
thought some of you might be interested in the following recent snowfall links:
Current US snowcover:
http://www.weather.com/maps/maptype/currentweatherusnational/uscurrentsnowcover_large.html
Northeast Current Seasonal Snowfall Total:
http://www.erh.noaa.gov/nerfc/graphics/snowmaps/sea1_today.jpg
Northeast Storm Total from 8am 12/5 to 8am 12/8:
http://www.erh.noaa.gov/nerfc/graphics/snowmaps/stf1_today.jpg
and also, the Mount Washington weather notes from Monday regarding why they recieved a fraction of what the nearby valleys got a short distance away:
04:13 AM Mon Dec 08, 2003 EST
The summit seems to be a nonstop lesson in amazing weather phenomena, but not always in the way one thinks. This weekends storm, that will likely go down in the record books as one of the biggest December storms of all time, did not play out as we had expected on the summit. While locations just a couple of miles away at the base of the mountain received 3 to 4 feet of snow, we have logged a measly 10 inches. These numbers baffled us at first. The marked disparity however has lead to some interesting conjecture.
Past storms of a similar nature have resulted in unbelievable quantities of snow for the summit, so what was different? At first we thought that wind alone was likely responsible for scouring the summit of snow but as we looked back at maps from older storms with large snowfall, winds were on the same order of magnitude. Thus there has to be another variable.
The theory that we've come up with is as follows. Think of yourself driving in your car in a light snow shower. What do you see? Snow flakes rush toward you and at the last second veer up and over the windshield without ever actually hitting the car. Now imagine this on a very large scale. The key is that the snow was so fine throughout the storm (as temperatures held in the low single digits) that it lacked sufficient mass to actually fall. Instead it remained airborne more like fog or mist. If the air had been warmer there would have been larger heavier flakes that both would have fallen more readily and also stuck to surfaces. Thus it was a combination of wind speed (which topped out at 98 mph) and the type of snow.
As such our snowfall measurements may be more appropriate than they seem. They also definitely represent ground conditions on the summit. This morning we were all appalled to see that the view (through the fog) looked negligibly different than it had before the storm.
The joke has been that instead of measuring snowfall we should measure the amount of snow that transited the summit during the storm. Perhaps a rough estimate of the density of snow in the air could have been made. Then by calculating the amount of air that moved past the summit we could have come up with a staggering figure of potential snowfall.
Alas, for now we are left in envy of our valley neighbors.
Neil Lareau - Summit Intern
Current US snowcover:
http://www.weather.com/maps/maptype/currentweatherusnational/uscurrentsnowcover_large.html
Northeast Current Seasonal Snowfall Total:
http://www.erh.noaa.gov/nerfc/graphics/snowmaps/sea1_today.jpg
Northeast Storm Total from 8am 12/5 to 8am 12/8:
http://www.erh.noaa.gov/nerfc/graphics/snowmaps/stf1_today.jpg
and also, the Mount Washington weather notes from Monday regarding why they recieved a fraction of what the nearby valleys got a short distance away:
04:13 AM Mon Dec 08, 2003 EST
The summit seems to be a nonstop lesson in amazing weather phenomena, but not always in the way one thinks. This weekends storm, that will likely go down in the record books as one of the biggest December storms of all time, did not play out as we had expected on the summit. While locations just a couple of miles away at the base of the mountain received 3 to 4 feet of snow, we have logged a measly 10 inches. These numbers baffled us at first. The marked disparity however has lead to some interesting conjecture.
Past storms of a similar nature have resulted in unbelievable quantities of snow for the summit, so what was different? At first we thought that wind alone was likely responsible for scouring the summit of snow but as we looked back at maps from older storms with large snowfall, winds were on the same order of magnitude. Thus there has to be another variable.
The theory that we've come up with is as follows. Think of yourself driving in your car in a light snow shower. What do you see? Snow flakes rush toward you and at the last second veer up and over the windshield without ever actually hitting the car. Now imagine this on a very large scale. The key is that the snow was so fine throughout the storm (as temperatures held in the low single digits) that it lacked sufficient mass to actually fall. Instead it remained airborne more like fog or mist. If the air had been warmer there would have been larger heavier flakes that both would have fallen more readily and also stuck to surfaces. Thus it was a combination of wind speed (which topped out at 98 mph) and the type of snow.
As such our snowfall measurements may be more appropriate than they seem. They also definitely represent ground conditions on the summit. This morning we were all appalled to see that the view (through the fog) looked negligibly different than it had before the storm.
The joke has been that instead of measuring snowfall we should measure the amount of snow that transited the summit during the storm. Perhaps a rough estimate of the density of snow in the air could have been made. Then by calculating the amount of air that moved past the summit we could have come up with a staggering figure of potential snowfall.
Alas, for now we are left in envy of our valley neighbors.
Neil Lareau - Summit Intern