Sunday 8:10 AM


Everything on track for excessive wet event for October.  Accumulating snow probably Monday Morning in town. Freezing level down to Village about 800AM to 900am Monday morning.  This is a little earlier now than Fridays guidance. Amounts still look good for 3 to 5 feet above 9,000 feet now as snow level is down about 500 feet during moister portion of event.

Remember, in order to break snowfall record for October, we need close to 68 inches at Snow Plot as there was 18 inches already fallen. Water content is likely to be there either way so precipitation should be enough.

What a way to kick off the water year beginning with October!!!!


9:00AM Update

Latest IVT guidance (GFS) from Scripts IVT puts the October 25th Event in the strong category now as compared to the January 27th event which was moderate, west of Mammoth Pass. The January 27, 2021 event dumped aprox 10 feet of snow on Mammoth Mt. However, this storm is much much warmer. Freezing level above Yosemite is between 9000 to 11,000 feet during the day Sunday during the beginning of the event. However, by Sunday night and especially after midnight, the freezing level begins to come down as indicated;  11:00PM (10,200ft) down to (8900ft) by 5:00AM Monday AM.  Between 5:00AM Monday and 11:00AM Monday 8900 to 7100ft. Then 11:00AM Monday to 5:00PM Monday; the Freezing level goes from 7100 to 6700 feet. Then from 6700 to 6100 feet Monday night.   It is important to realize that in an saturated airmass,  the Freezing level is close to the snow level, within 500 feet. contrarily, micro physical processes can allow snow to fall much further down in elevation from the dendritic growth zone, if temperatures are cold enough in that zone and the vertical motion is favorable.  All in all, the main point is, precipitation for the Month of October may be historic for Mammoth Mt, whether we get the additional snowfall of 68 inches in addition to the 18 inches the mountain has already received.


Next update Sunday AM……………….

Dr Howard and the Dweebs…………………..:-)


The stage is set for a good wholloping AR for California this weekend. The updated GEFS IVT plume forecast shows a magnitude for the coast, from the 06Z data at the mouth of the Bay Area, approaching 1200 (KG) (MS) which is in the extreme category for the (IVT) Integrated water vapor transport. For our part of the Sierra, it shows about 900 (KG) (MS) for the IVT, in the strong category.    This is on par with the January 26th-27th, 2021 AR. This AR will give relief to the many reservoirs throughout Central and Northern CA,  However, what about the mudslide threat for areas below the burn scars? Now I will say that the ECMWF model is not nearly as wet.  However, if you average them out it is still very impressive!

The Models are coming in line with some 5 to 7 inches of water for just west of the Mammoth Sierra Crest. The freezing level is high to begin with. So although the snow level may begin lower, it will rise to between 9,000 to 10,000 feet initially. However,  once the cold air induced vertical motion begins, the snow level will come down into the town Saturday Night or Sunday, then into Monday.   Expect excessive snowfall for October, with potential “Event History” in the making for record snowfall on Mammoth Mt.  The current record is 85.6 inches during October of 2004.  So far this October, Mammoth Mountain has received 18 inches.  Only need another 68 inches of snow by Halloween to break the October record.  This should be a 100+  year record for October based upon precipitation records for the Sierra dating back to 1895.