Winter Storm DSS Review

10-13 January 2013

Paul FrisbieDennis Phillips

Matthew Aleksa

Timeline (How Did Things Change?)

2. WinterStormWatchIssued

3. WordingChangedOn Watch

4. WatchUpgraded

5. High Confidence(San Juans and Pagosa,Valley inversions break,

Cold front timing)Low Confidence

(Post frontal snow)

6. Uinta BasinAdded to Advisory

7. QuickerCold Front

8. Vernal: 4-6”report. Upgraded

to warning.

9. Dynamics shiftedon to plains.

Lee-side sfc low.Scattered convective

Showers.

10. Early cancellations.Dry and cold air

mass post-frontal.

WED 1/09 THU 1/10 FRI 1/11TUE 1/085am 5am 2pm 11pm 10am 11pm 6am 9am 11am 4pm 6am

SAT 1/12

Special WeatherStatementIssued

Photo: Craig Daily Press28 January 2008CSP 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 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

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 5PM700 mb Temperatures, RH, and Wind

Friday 11th 5 AM MST

Saturday 12th 5 AM MST

Saturday 12th 5 AM MSTFriday Max

Saturday Max Sunday Min

Observations [Temp, WG (mph), Wx]:

Station 6AM 9AM Noon 3PM 6PM

Douglas Pass (CDOT)15 10 8 10 6G51 G30 G27 G21 G13

Rabbit Ears (SNOTEL) 19 15 9 6 5

Wolcott (CDOT) 25 23 26 17 14G18 G12 G13 G15 G17

Skyway (CAIC) 5 1 0 1 -4G31 G23 G23 G16

Vail Pass – CDOT Yard 15 9 4 3 -2 (CAIC) G10 G21 G24 G21 G17

Dowd Junction (CDOT) 22 17 20 13 12G45 G44 G37 G35 G30S+ S- S- S--

Taylor Park 19 14 14 12 9

Storm King Mountain 16 13 9 7 5(Raws) G35 G18 G11 G12 G10

Observations [Temp, WG (mph), Wx]:

Station 6AM 9AM Noon 3PM 6PM

Aspen (CDOT) 34 28 28 19 18G15 G16 G12 G12

S- S- S-

Telluride – Lawson Hill 15 10 14 13 3(CDOT) G30 G21 G23 G20 G11

S- S- S-- S--

Lizard Head Pass (SNOTEL) 12 7 7 9 1

Red Mountain Pass (SNOTEL) 11 4 4 2 -5

Molas Pass (CAIC) 9 2 0 0 -4G32 G26 G24 G20 G13

Durango (CDOT) 25 20 23 20 15G22 G21 G22 G18 G11S- S- S-- S-- S--

Pagosa Springs (CDOT) 21 18 17 18 11G29 G22 G27 G17 G15

Storm Total Snowfall for Colorado

Questions or Comments?