Winter Storm DSS Review January 2013 Paul Frisbie Dennis Phillips Matthew Aleksa

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

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.”

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 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

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?)

Storm Review

SNOW ACCUMULATIONS

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

Friday 11 th 5 AM MST

Saturday 12 th 5 AM MST

Friday Max Saturday MaxSunday Min

Observations [Temp, WG (mph), Wx]: Station6AM9AMNoon3PM6PM Douglas Pass (CDOT) G51G30G27G21G13 Rabbit Ears (SNOTEL) Wolcott (CDOT) G18G12G13G15G17 Skyway (CAIC) G31G23G23G16 Vail Pass – CDOT Yard (CAIC)G10G21G24G21G17 Dowd Junction (CDOT) G45G44G37G35G30 S+S-S-S-- Taylor Park Storm King Mountain (Raws)G35G18G11G12G10

Observations [Temp, WG (mph), Wx]: Station6AM9AMNoon3PM6PM Aspen (CDOT) G15G16G12G12 S-S-S- Telluride – Lawson Hill (CDOT)G30G21G23G20G11 S-S-S--S-- Lizard Head Pass (SNOTEL) Red Mountain Pass (SNOTEL) Molas Pass (CAIC) G32G26G24G20G13 Durango (CDOT) G22G21G22G18G11 S-S-S--S--S-- Pagosa Springs (CDOT) G29G22G27G17G15

Storm Total Snowfall for Colorado

Questions or Comments?