Powder Forecast – Tuesday February 11th, 2025
Ted Schlaepfer CCM —- Mammoth Mountain WeatherGuy
Snowfall forecasts are valid at the Sesame snow course (Main Lodge) for the prior 24 hours as reported in the 6-7 AM morning snow report.
**Snowfall forecast confidence ranges from very low (1) to very high (5)
Wed 2/12 = 0”
Thu 2/13 = 7 – 10” (H20 = 0.75” – 1.00”)**3
Fri 2/14 = 34 – 42” (H20 = 4.00” – 5.50”)**3
Sat 2/15 = 2 – 4” (H20 = 0.25” – 0.35”)**3
Sun 2/16 = 0”
Mon 2/17 = 0”
Tue 2/18 = 0 – 1”
Wed – Fri 2/19 – 2/22 = 0 – 1”
February Snowfall = 21”
February Forecast = 75 – 90”
Detailed 4-day Snowfall Forecast:
Wed 2/12 – No snowfall expected during the day, then moderate to heavy snowfall develops overnight, accumulations 7 – 10” at Main by Thursday AM, ~12” up top
Thu 2/13 – Blizzard conditions during the day with heavy snowfall and strong winds followed by continued moderate to heavy snowfall overnight. Accumulations 34 – 42” at Main by Friday AM, ~48” up top
Fri 2/14 – Moderate snowfall during the morning tapers off during the afternoon and ends the evening. Accumulations 2 – 4” at Main by Saturday AM, ~6” up top
Sat 2/15– No snowfall expected
Forecast Summary:
Short Term (Days 1 – 4):
The current infrared satellite image (below) this afternoon shows clouds moving into CA associated with a warm front and weather system just off the coast. Another weather system is moving into the eastern Pacific and that is the storm of interest this week.
The first weather system will slide south of Mammoth overnight with just clouds and the next storm system will be positioned just off the coast on Thursday morning (image below). It is a fairly deep closed upper low and will produce good southwest upslope flow into the Sierra with an embedded weak atmospheric river to maximize precipitation output.
Snowfall will develop overnight Wednesday and should be very heavy during the day Thursday with generally blizzard conditions. It is a good chance that most, if not the entire mountain is closed on Thursday due to the intense snowfall. Moderate to heavy snowfall will continue overnight Thursday and into Friday before snowfall tapers off during the afternoon, ending evening. Dry weather returns over the weekend.
Snow levels will start out around 6-7000 feet overnight Wednesday before rising slightly to 7-7500 feet during the day, and then decrease to 5500 feet Thursday night and into Friday morning. So it will be another round of Sierra cement with snow ratios in the 7-8:1 range by Thursday PM after starting out around 10:1.
Model QPF is fairly impressive for a single storm event with the GFS model the wettest at around 6” liquid (image below). Both the ECM (two images below) and the NBM (three images below) show slightly less and in the 4-5” range. ECM is forecasting three feet of snowfall in town too (4 images below). Forecast favors the ECM mean showing around 4.75” liquid that would translate to around 40” at Main and 4-5 feet up top. So lots of deep powder on Friday and Saturday, expect a slow opening for avy control.
Long Range (Days 5+):
The longer-range guidance is saying that a mostly dry weather pattern will return next week and into the following weekend. That super long range models are then saying the pattern may become active again toward the very end of the month and into March.
The ECM model moves two weak upper-level short-wave troughs southward through the state on Monday (image below) and around Thursday (two images below) next week. Both are moving from the northwest which is generally a dry direction.
The ECM model is only showing very light amounts on Monday (three images below) and again Thursday. Thus, there is only a chance for light snowfall both days and amounts right now look to be in the dust on crust category. Hopefully that will trend upward.
The 8-15 day pattern is favored to be dry with the ECM EPS showing below normal precipitation for the state (image below). The GFS ensemble is also dry and similar to the ECM EPS. Thus, it appears we may see dry weather for around week or longer over the last part of the month.
The fantasy range guidance is still saying precipitation may return over the very last part of the month and into March. The ECM EPS has slightly above normal precipitation returning over that period (image below) and keeps slightly above normal precipitation ongoing through most of March. The GFS extended is not as bullish with dry weather extending into early March before wet weather returns during the month. Either way, both models say there will be more powder days.
