New snow/sleet is the amount of snow and/or sleet that
has fallen since your last observation or since the snow and/or sleet
began. Sleet is small chunks of ice
that are like small hailstones. (This
is different from freezing rain, see below.)
Recommended equipment:
-
Snowboard
-
Ruler or yard stick
It is recommended that the snowboard be a flat piece
of plywood as close to a square as possible and at least 144 square inches (1
square foot). It is probably best to
have a 2 or 3-foot square (or nearly square) snowboard. A larger snowboard is easier to find after
several inches of snow. A wooden deck
away from buildings and trees is a suitable substitute.
The snowboard should be placed in a grassy area where
snow accumulates uniformly. Do not
place the snowboard under tree branches or wires or near buildings, homes,
automobiles, roads, driveways or sidewalks.
It you live in a heavily wooded area, try to locate your snowboard in an
exposed clearing or in an area where there are less trees. Do not place the snowboard where snow from a
neighbor’s snow blower might land. The
snowboard does not have to be on the ground all winter, just when snow is
expected. (I don’t want you to kill
your grass by leaving the snowboard out all winter.)
When you make an observation, use a ruler or yard
stick and measure the depth of the snow and/or sleet on the snowboard to the
nearest half-inch at several places.
The average depth is the new snow and/or sleet since the last
observation reported to the nearest ½ inch.
When you are done making measurements, wipe all the snow and/or sleet
off the snowboard.
It is fairly easy to measure new snow if the wind is
light and there is no blowing and drifting snow. When there is a lot of wind causing blowing and drifting, there
may be no snow on your snowboard. In
this case, or if you feel the amount on the snowboard is not representative of
how much snow fell, make a good guess on how much new snow fell.
Guide to Estimating Ice Accumulation
Recommended equipment: - Ruler
Ice accumulation occurs when rain falls with surface
temperatures below freezing. This is
commonly called freezing rain.
The best way to measure ice accumulation is to break
off a very small branch/twig from a tree.
Use a ruler to measure the thickness of ice in tenths of an inch. There may be one side of the branch or twig
with a greater thickness of ice than the other side. In this instance, please report the average thickness of ice
buildup.
A half of an inch of ice buildup will usually start to
bring down tree limbs and power lines.
Guide to Measuring Total Depth of Old and
New Snow/Sleet
Snow/Sleet depth is simply the depth of snow/sleet on
the ground, both old snow/sleet and new snow/sleet. Since snow tends to compact and may melt from underneath, your
last total snow/sleet depth plus your new snowfall usually will be more than
your most recent total snow/sleet depth.
In addition, sleet or freezing rain falling on a fresh snow cover will
cause a lot of compaction.
Recommended equipment: - Ruler or yardstick.
After making a new snowfall measurement, measure the
total snow depth of both old and new snow.
To measure snow depth, simply go around an area where there is an
average snowfall and make 5 to 10 measurements. Make sure all measurements are at least 5 feet apart. The average of these measurements is the
snow depth. Be sure to avoid making
measurements in snowdrifts, in areas where most of the snow has been blown
away, under trees, or near houses. If
there has been any wind at all, you will likely find significant differences in
depth.
Reporting Procedure by Phone
Please phone the National Weather Service at 1-800-221-2856 as soon as
possible after making an observation when an inch or more of new snow and/or
sleet or any ice accumulation has occurred.
We would like to have all reports for the 7 AM observation by 8 AM, for
the 1 PM observation by 2 PM, for the 7 PM observation by 8 PM, and the 1 AM observation
by 2 AM.
Please take an observation and report it
to the National Weather Service when either one of the following criteria are
met:
1)
New snow
and/or sleet accumulation (if equal to or greater than an inch) since the last
observation or since the snow and/or sleet began. Also include duration of time in which the new snow and/or sleet
fell.
2)
Any ice
accumulation.
There is no need to call us when the
above criteria (1 or 2) are not met. If
you are calling us to report one of the above mentioned items, please include
the following information as well:
-
Your location.
-
Depth of old and new snow and/or sleet.
-
Current weather (related to precipitation type and
intensity, if any) including any blowing or drifting snow. This would also include current temperature,
if you have a thermometer.
During an active winter weather event we will make sure that additional
people are here to take your reports.
In addition, you may phone in observations at other times, if you feel
the information would be significant and the criteria 1 or 2 are met.
Reporting Procedure via SKYWARNTM AMATEUR RADIO NET
During significant and widespread winter weather events, SKYWARNTM net
controllers will likely be running a mini winter weather net on 146.745 up to
three times a day to take winter weather reports. The times of these nets will be from 7 to 8 AM (for 7 AM
observations), 1 to 2 PM (for 1 PM observations), and 7 to 8 PM (for 7 PM
observations). If the mini SKYWARNTM
winter weather net is not active, please relay your observation to our office
using the 800-phone number.
Observations relayed to the net controller will be passed to the
National Weather Service.
Examples:
Snow starts to fall at the house of Jim Smith at 2 PM, some sleet
begins mixing in around 5 PM. At 7 PM,
Jim takes an observation and comes up with 4 inches of new snow/sleet. Jim measures a total depth of old and new
snow/sleet at 5 inches. Jim calls the
National Weather Service and reports that 4 inches of new snow/sleet feel
between 2 PM and 7 PM and the total snow/sleet depth at 7 PM was 5 inches. In addition, Jim reports that snow and sleet
were still falling and the temperature was 28 degrees.
Jack Cunningham measures a snow depth of 10 inches at his 7 AM
observation. At 1 PM Jack relays to the
National Weather Service using the 800# that 5 inches of additional snow fell
from 7 AM to 1 PM and the snow depth is now 13 inches. (Note, melting or compaction occurred)
You take an observation at 1 PM and report 3 inches of new snow in the last 6 hours and a snow depth of 5 inches. You take another observation at 3 PM and now have 4 more inches of snow and a snow depth of 8 inches. You call this report into our office. (Note, melting or compaction occurred)