1. Winter Storm DSS Review 10-13 January 2013 Paul Frisbie Dennis Phillips Matthew Aleksa

2. Timeline (How Did Things Change?) 2. Winter Storm Watch Issued 3. Wording Changed On Watch 4. Watch Upgraded 5. High Confidence (San Juans and Pagosa, Valley inversions break, Cold front timing) Low Confidence (Post frontal snow) 6. Uinta Basin Added to Advisory 7. Quicker Cold Front 8. Vernal: 4-6” report. Upgraded to warning. 9. Dynamics shifted on to plains. Lee-side sfc low. Scattered convective Showers. 10. Early cancellations. Dry and cold air mass post-frontal. WED 1/09THU 1/10FRI 1/11TUE 1/08 5am 2pm11pm10am11pm6am9am11am4pm6am SAT 1/12 Special Weather Statement Issued

3. Photo: Craig Daily Press 28 January 2008 CSP advised motorists to seek shelter From FEMA: If stranded in a vehicle during a winter storm with extreme cold: “Run the engine and heater about 10 minutes each hour to keep warm. When the engine is running, open a downwind window slightly for ventilation and periodically clear snow from the exhaust pipe. This will protect you from possible carbon monoxide poisoning.”

4. Special Weather Statement/Watch – Potential Impact Based Talking Points Significant accumulations of powdery snowfall (average confidence) Gusty surface winds in the post frontal environment (above average confidence) Falling Daytime Temperatures - Highs 15-25 and falling (above average confidence) Warnings/Advisories/Outlooks – May NOT Always Focus on Snowfall Amounts If stranded – Hypothermia Risk Clogged exhaust (from snow) and Running Engine to Stay Warm – Increased Carbon Monoxide Risk Risk to Backcountry Recreationalist

5. Other Considerations! Travel Day? Broncos – Ravens NFL Playoff Game is the following day after storm. Falling Daytime Temperatures (Wind Chill a factor) – Not uncommon in winter, but not typical. Do “Advisories” address the enhanced Winter Weather Hazards? Avalanche Hazards (Snowfall and Wind)? Decision: Used “Forecaster Discretion” – Issued strongly worded SPS/Watch Statement Average Confidence that snow amounts may surprise to the upside (track of the upper level system is questionable - does upper low move over western Colorado or shear northeast into Wyoming?)

6. Storm Review

7. SNOW ACCUMULATIONS

8. Friday Afternoon 5PM 700 mb Temperatures, RH, and Wind

9. Friday 11 th 5 AM MST

10. Saturday 12 th 5 AM MST

11. Friday Max Saturday MaxSunday Min

12. Observations [Temp, WG (mph), Wx]: Station6AM9AMNoon3PM6PM Douglas Pass (CDOT)15108106 G51G30G27G21G13 Rabbit Ears (SNOTEL)1915965 Wolcott (CDOT)2523261714 G18G12G13G15G17 Skyway (CAIC)5101-4 G31G23G23G16 Vail Pass – CDOT Yard15943-2 (CAIC)G10G21G24G21G17 Dowd Junction (CDOT)2217201312 G45G44G37G35G30 S+S-S-S-- Taylor Park191414129 Storm King Mountain1613975 (Raws)G35G18G11G12G10

13. Observations [Temp, WG (mph), Wx]: Station6AM9AMNoon3PM6PM Aspen (CDOT)3428281918 G15G16G12G12 S-S-S- Telluride – Lawson Hill151014133 (CDOT)G30G21G23G20G11 S-S-S--S-- Lizard Head Pass (SNOTEL)127791 Red Mountain Pass (SNOTEL)11442 -5 Molas Pass (CAIC)9200-4 G32G26G24G20G13 Durango (CDOT)2520232015 G22G21G22G18G11 S-S-S--S--S-- Pagosa Springs (CDOT)2118171811 G29G22G27G17G15

14. Storm Total Snowfall for Colorado

15. Questions or Comments?