The Weather Wire
November 2009 Volume 17 Number 11
Avg High - 54.
Avg Low - 31.1
Snow - 17.2"
Season Snow - 17.2"
Precipitation - 1.36"
Avg High - 51.5
Avg Low - 23.5
Avg Snow - 10.7"
Avg Precip - 0.98"
How to Properly Measure Snow
After the big October snowstorm and looking at all the varying snowfall reports from citizens and trained weather spotters I thought it would be helpful to go over how to properly measure snowfall.
Measuring snow can be fun and it is relatively easy to get a good measurement if you follow just a few simple guidelines. Measuring snow is fun since the best time to measure snow is while it is snowing or shortly thereafter so you will get to enjoy the snow covered scenery. One of the two biggest mistakes made by people who measure snow is that they may measure the snow the next morning after the snow has ended or melted some resulting in a lower measurement or they measure drifted snowfall resulting in higher measurements. For instance if 5” of snow fell while you were at work during the day and then you came home and 2” had melted resulting in 3” measured when you got back then the 2” would be lost. Another issue is that homes and their interaction with the wind result in drifting and in some cases the “spotter” may measure a drifted area instead of the average. Below are some quick and easy guidelines on how to measure snowfall taken from NWS website: http://www.erh.noaa.gov/gyx/measuring_snow.htm .
MEASURE SNOW WITH A MEASURING STICK
Find a location where the snow appears to be near its average depth. Avoid drifts or valleys. Look for a flat, somewhat open area away from buildings and trees. Some trees in the distance may be helpful in making a wind break, preventing drifting, and thus providing for a more even distribution of the snow. Measure the depth with the snow measuring stick (aka "the common household ruler") at several locations and use an average. Traditionally ten measurements are made and the average value is the snow depth. When snow has fallen between observation times and has been melting, measure its greatest depth on the ground while it is snowing, or estimate the greatest depth. During heavy snowfall some of the actual total may be lost due to compaction of the column by the weight of the snow, during these times it may be best to estimate a slightly higher value if snow has been falling at a heavy rate for several hours since the last actual measurement. If all snow melted as it fell, you can report a trace for the snowfall.
MEASURING NEW SNOW FALLING ON TOP OF OLD SNOW
When fresh snow has fallen on old snow, it is necessary to measure the depth of the new snow (in tenths of inches). Snow boards provide the best method of taking measurements in this case. Sometimes if the old snow has settled or partially melted enough to develop a crust or to be noticeably denser than the new snow, it may be possible to insert the snow stick until it meets the greater resistance of the crust of old snow, and to use this depth as the amount of new snow having fallen.
USE OF A SNOW BOARD
Snow boards are laid on top of the old snow when there is any possibility of new snow falling. Push them into the snow just far enough that the top of the board is nearly level or just above the top of the old snow. After each observation, boards should be cleaned and placed in a new location. Because of evaporation or drifting, they may need adjusting daily to assure that the top of the board remains flush with the old snow. A clean sidewalk or open cement area where there is some protection from the wind and drifting is a good alternative (if the ground is frozen) to using a snow board. You still need to clean an area off before the snow starts and between measurements in order to accurately measure the newly fallen snow.
Just by being timely and aware of drifting can be very helpful in measuring new snow. Skyview would like to thank all of our spotters for their valuable information and the time they spend on snow measurements.
With the widespread precipitation of the last several months, little areas of drought remain in Colorado, though some dry areas have developed in southwestern Colorado.
The map below shows forecasted temperature deviances for November 2009. As can be seen, it is expected that all of Colorado to have above normal temperatures for the month of November 2009.
The map below shows forecasted precipitation deviances for November 2009. All of Colorado is expected to have normal precipitation for November 2009.
Little in the way of drought remains in Colorado, with no changes expected.
October of 2009 provided plenty of weather highlights with numerous records tied or broken and a major winter storm for the latter part of the month producing up to 20" of snow or more in the Denver Metro area. This October was also very cold becoming the 2nd coldest October on record with average highs more than 11 degrees below normal. Average lows were only 4.8 degrees below normal resulting in a monthly mean temperature of 42.9 compared to 51.0 on average. Much of the cold can be attributed to the multiple day storm with 5 record lows tied or broken. For the month Denver ended up with 17.2" of snow at DIA with 15.3" coming during the big storm. The 17.2" is 13.1" above normal and makes up for the lack of snow at DIA during the month of September, but on the season DIA is only 9.7" above normal. Many other Front Range locations have reported much higher snowfall with around 33% of an average year already. The total precipitation for the month was 1.36" compared to 0.99" on average and pushes our yearly total to 17.18" which is 4.0" above normal. What a change compared to the past few years. There was only one high temperature record tied during the month and it came just ahead of the big snow with a high of 84 on the 18th of the month. Percent of possible sunshine was not recorded this month, but I would have to think that it was well below normal as well.
After the big storm in October the weather pattern has been tranquil with record breaking heat the first week of November helping to melt all of the leftover snow. Don't let the nice weather fool you as November is typically the 2nd snowiest month of the year behind March. The weather pattern will likely become more active towards over the next week and continue through the end of the month with a 2-4 measurable snows likely by month end. There is around 0.98" of precipitation on average and will likely end up just a bit short of normal but we are well above normal for the year so anything extra will be gravy on the top of what already has been a good water year for the Front Range.
Sunrise/Sunset (Jul - December Denver area)
Sept 2009 to Apr 2010