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Trends in Spatial and Temporal Variability of Snowfall Totals and Events in Wisconsin, 1974 - 2010
1.
Presented by: Daryn Hardwick
Graduate, Geography Department, Saint Cloud State University
Faculty Advisors: Dr. Keith Rice, UWSP Geography Department
Eugene Martin, UWSP Geography Department
2. Purpose
o To better understand winter climatology for the state of
Wisconsin
Hypothesis
o Ha = There has been a decrease in both the amount of snowfall
and individual snowfall events in the state of Wisconsin between
1974 and 2010.
o Ho = There has been no change in the amount of snowfall or
individual snowfall events in the state of Wisconsin between
1974 and 2010.
3. Economic Benefits
o Winter Tourism - $7.9 billion annually
o Cold Water Fishing - $2.3 billion/year industry
o Snowpack Water Storage saves between $2.3 - 348 billion/year
Economic Costs
o Snow Removal - $2 billion/year
o Road Closures - $2.5 billion/year
• Lost retail trade, wages, and tax revenue
o Damage to Utilities
• $2 billion lost in 1994 snow storm in Mississippi
o Flooding
• $4.7 billion lost in 1997 Red River flooding in ND and MN
4. The Impact of Snow/Winter Events on Humans:
o 23.4 deaths per year caused
o 161.7 injuries per year caused
o $484 million in damage caused annually
Groundwater Recharge
o Urie (1966) determined about 2/3 of yearly groundwater
recharge contributed by winter precipitation
5. Decline in snow cover extent and duration
o Choi et al. 2010, Davies 1994, Dêry and Brown 2007
Great Lakes studies
o Burnett et al. (2003) - increase in snowfall and both the lee and
windward sides
o Norton and Bolsenga (2007) – increase in lake-effect snowfall
Wisconsin snowfall
o Kunkel et al. (2009) – slight increase in snowfall
6. Data
o National Weather Service Cooperative Observer Program
• Precipitation, Snowfall, and Snow Depth
• October – April
• 1974/75 – 2009/10 seasons
• 152 weather stations, 11 out-of-state
Analyses
o Station Homogeny
o Season Averages and Event Totals
o Snowfall/Precipitation Ratio
o Regression lines (trends)
7. Station Homogeny – having <10% missing data over the
study period (Kunkel et al. 2009)
o 137/152 (90%) determined homogenous for precipitation
o 120/152 (79%) determined homogenous for snowfall
o 78/152 (51%) determined homogenous for snow depth
o Only stations suitable in both precipitation and snowfall were
used in final analysis, 117 stations (77%)
2008-2010 Seasons
20. Increase in Winter Precipitation
o Significant at the ≥ 95% confidence level (p = 0.0001)
Increase in Winter Snowfall
o Not significant at the ≥ 95% confidence level (p = 0.3624)
Decrease in Snowfall-to-Precipitation Ratio
o Not significant at the ≥ 95% confidence level (p = 0.0526)
Increase in Days with Precipitation
o Significant at the ≥ 95% confidence level (p = 0.0365)
Decrease in Days with Snowfall
o Significant at the ≥ 95% confidence level (p = 0.0271)
2008-2010 Seasons
o Anomaly or new trend?
21. Self Critiques
o Climate data inherently unreliable?
o Number of Events in a given season
o Are t-test’s suitable for climatic data?
o Is 36 years enough for a climate study?
Future Research
o Investigate above critiques
o Do El Niño or La Niña have an effect?
o Spatial and temporal trends in temperature
o Trends in Snow Cover and Snow Depth
o Snowfall-to-Precipitation Ratio
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Services.Report prepared for NOAA's National Operational data, Data used: 1974-2010.
Hydrological Remote Sensing Center.
NOAA NWS Office of Climate, Water, and Weather Services, Natural Hazard
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