#1: What is snowpack? Snowpack is the total amount of snow on the ground. The “pack” in snowpack refers to snow being packed down as new snow falls on top of old snow. Denver Water photo: Jones Pass
1. #1: What is snowpack? Snowpack is the total amount of snow
on the ground. The pack in snowpack refers to snow being packed
down as new snow falls on top of old snow. Denver Water photo:
Jones Pass
2. #2: Why do we care about snowpack? Most of the Denver areas
water supply comes from mountain snowpack that melts. The water
(also known as runoff) runs downstream and is captured in our
reservoirs.
3. #3: What do we look for in snowpack? Depth of the snow is
not as important as how much moisture is in the snow. Experts
measure snow water equivalent to judge how much water the snowpack
will yield. Snow water equivalent is the depth of water that would
result if the snow were melted. Which begs the question. Denver
Water photo: Winter Park
4. #4: How do we measure snow water equivalent? Its typically
measured one of two ways. We can manually measure it by capturing
snow in a sampling tube, weighing the snow and using a formula to
convert weight to snow water equivalent. Or Denver Water photo:
Winter Park
5. #4: How do we measure snow water equivalent? Automated
SNOTEL sites maintained by the Natural Resources Conservation
Service of Colorado measure the weight of snow captured on special
sensors and convert it to snow water equivalent. Photo courtesy of
NRCS Colorado
6. #5: How do we determine if snowpack is normal? We compare
current conditions to the same date historically. Snowpack is
typically expressed as a percentage. (Those are the numbers you see
on snowpack maps.) A number below 100 percent means that snowpack
is below the historic normal for that date; a number above 100
percent means above-normal snowpack. Denver Water photo: Jones
Pass
7. #6: Where do we capture snowpack runoff? Denver Water
captures runoff from snowpack in the Upper Colorado River and Upper
South Platte River basins. But we dont capture runoff everywhere in
those basins. The snowpack must be in areas above points where we
divert water to flow into our reservoirs.
8. #7: What other factors affect snowpack? Sun, wind and dust
are all factors. Dust makes snow surface darker, causing snow to
absorb more of the suns energy and melt faster. Strong, dry winds
can blow snow off mountain peaks before melting occurs. And early,
warm temperatures can dry out the ground, making it more likely to
absorb snowpack runoff before the water ever reaches our
reservoirs. Photo courtesy of Center for Snow and Avalanche
Studies, Silverton, Colo.
9. #8: What happens to snowpack when it rains? It depends on
the temperature of both the snowpack and the raindrops. Sometimes
the raindrops freeze when they hit the snow, and the snow water
equivalent increases. But if the rain is warmer than the snowpack,
the rain can cause melting. Denver Water photo
10. #9: When should we closely monitor snowpack? Any
precipitation any time helps the Denver areas supply. Heavy, early
winter snows can provide a cushion should weather turn dry later,
but a wet spring can also make up for a dry winter. We monitor the
snowpack almost year-round, but our experts pay particular
attention as winter turns to spring, since March and April are
typically our snowiest months. Denver Water photo
11. To sum it up... Regardless of the amount of snow in the
Rocky Mountains in any given year, the water the snowpack produces
will always be an incredibly precious resource. We should
understand how our world is all connected and be efficient in our
use of water. Denver Water photo: Cheesman Reservoir