Minnesota s Changing Climate: Winter Impacts

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1 Minnesota s Changing Climate: Winter Impacts Dr. Mark Seeley Climatologist/Meteorologist Dept of Soil, Water, and Climate University of Minnesota 15 th Annual Road Salt Symposium Minnesota Landscape Arboretum Chaska, MN Feb 4, 2016

2 This day in history Lunch outside! 65 degrees F at Tracy, MN (Lyon County) Feb 4, 2005 Dress in layers! -52 degrees F at Detroit Lakes, MN (Becker County) Feb 4, 1907 Severe ground blizzard in southern MN, closed Hwy deaths Feb 4, of snowfall at Halstad, MN (Norman County) Feb 4, 2008

3 Topics to be covered: Temperature trends and patterns Precipitation trends and patterns Consequences

4 RECENT SIGNIFICANT CLIMATE TRENDS IN MINNESOTA AND THE WESTERN GREAT LAKES TEMPERATURE: WARM WINTERS AND HIGHER MINIMUM TEMPERATURES MOISTURE: AMPLIFIED PRECIPITATION SIGNAL, THUNDERSTORM CONTRIBUTION

5 Minnesota weather and climate history National Climate Assessment 2014 NOAA Climate Monitoring and Global and National Assessment Divisions IPCC 5 th Assessment Information Resources Used

6 Geographic Disparity in Temperature Change From IPCC AR5 Report

7 Seasonality in temperature change (IPCC-2007) Figure 3.10

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10 Disparity in the pace of climate change relative to temperature

11 Minnesota Mean Annual Temperature Trends Temp trend is upward and more frequently above the 90 th percentile, pace is 2 F per century.

12 Winter Spring Seasonal Statewide Temperature Trends in MN Summer Fall

13 Statewide Change in average winter minimum temperature is 5 F per century

14 LARGE CONTRIBUTION FROM WARM WINTERS Top 12 warmest Dec-Feb periods in Minnesota since 1895 based on aggregate mean temperature (F) *Historical median value 10.3 F, the last winter below that value was in

15 January February March April May June July August September October November December Annual Minnesota State Averaged Temperature Trends Maximum Temperature Trend Minimum Temperature Trend Difference (Max minus Min) degrees F per century

16 Trends in average winter minimum temperatures Rochester, MN Period of Record Ave Min Temp in Deg. F Jan 1.9 Jan 2.7 Jan 3.7 Jan 7.7 Feb 7.6 Feb 8.1 Feb 10.6 Feb 12.4 Mar 19.2 Mar 21.3 Mar 22.6 Mar 24.3

17 Trends in average winter minimum temperatures Milan, MN Period of Record Ave Min Temp in Deg. F Jan 4.3 Jan 0.9 Jan 0.3 Jan 3.7 Feb 2.3 Feb 5.3 Feb 8.2 Feb 9.3 Mar 15.1 Mar 19.2 Mar 21.0 Mar 22.0

18 Frequency of temperatures -30 F or colder at Pokegama Dam, MN average 9 nights per year average 2 nights per year Frequency of temperatures -30 F or colder at Grand Rapids, MN average 5 nights per year average 3 nigthts per year

19 Remember February 2, 1996? Location Low Temperature Littlefork -50 F Grand Rapids -41 F Thorhult -51 F Park Rapids -51 F Embarrass -54 F Tower -60 F Leech Lake -46 F Cass Lake -48F Remer -51 F

20 Net Change in Precipitation Over Land From IPCC-AR5 Report

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23 Geographic Disparity in Precipitation Change-IPCC 2013

24 Trend in annual precipitation for MN

25 Average Annual PPT , in Average Annual PPT , in Avg. Annual PPT, in Average Annual PPT , in < > 30 Average Annual PPT , in Source: MN-SCO

26 Winter (D,J,F) Spring (M,A,M) Seasonal Trends in MN Precipitation Summer (J,J,A) Fall (S,O,N)

27 Change in Annual Precipitation Normals at Milan, MN PERIOD AMOUNT (IN.) percent increase since Extremes 7.91 in 1976, in 1995

28 Change in Annual Precipitation Normals at Faribault, MN PERIOD AMOUNT (IN.) percent increase since period Extremes: in 1910, in 1951

29 Change in Annual Precipitation Normals at Windom, MN PERIOD AMOUNT (IN.) percent increase since period

30 Measurable Attributes of Precipitation Quantity Type (liquid,frozen) Intensity (9-15 ) Frequency ( days) Duration (10 days) Seasonality (shifting) Landscape relationship (interception, absorption, runoff, evaporation)

31 Radiosonde history of PW at MSP since 1948 Most record high values have occurred since 1990

32 Snapshot of expectations: <10 years Strength of expected impact from climate change Highest High Moderately High Moderately Low Low Lowest Hazard Expectations through 2024 Extreme cold Continued decline in severity, frequency Extreme rainfall Unprecedented events possible Heavy snowfall Severe thunderstorms & tornadoes Major events still likely as increased water vapor offsets increased temps Return to active conditions likely but unpredictable Heat waves Drought Expect at least one significant episode, even if within historical bounds From MN State Climatology Office

33 Features of change in winter climate of Minnesota Change in depth and duration of soil and lake freezing Increased frequency of freeze/thaw cycles Shorter continuous snow cover season More frequency intense precipitation events on the perimeter of winter More frequent mixed precipitation (liquid/frozen), and heavy snowfall events in the core of winter Change in storm sewer runoff design and culvert design for higher capacity to discharge runoff