Mammoth Mountain Ski Patrol 2020-21 Storm Summary - Sesame Snow Study Site 9,000' (2,743m)
Date Base Depth  HN24(") SWE Rain % Density StormSnow " Storm SWE " Season Snow Season SWE Season Precip Base Hi Temp Base Lo Temp Notes
11/07/20 4.0 3.0 0.45   15 3.0 0.45 3.0 0.45 0.58 43 16 Extra precip was ice from melted snow on board.  Did not rain. Brief clearing before PM snow 
11/8/2020 10.0 6.0 0.47   8           27 16  
11/9/2020 13.0 5.0 0.51   8 14.0 1.43 14.0 1.43 1.56 21 6 Pluvio 1.49"YTD
                           
11/18/2020 7.0 1.0 0.15   15           42 24  
11/19/2020 15.0 6.0 1.20   20 7.0 1.35 21.0 2.78 3.27 30 22 5.5" snow with 1.36Met fell during ops hrs 11/18. Pluvio 3.04YTD
NOV Total   21.0 2.78                    
12/12/2020 15.0 2.0 0.25 .03? 13 2.0 0.25 23.0 3.03 3.83 35 22 Snow started around 1am.  Light snow almost drizzle at 6am obs
                           
12/14/2020 21.0 8.5 1.30   16 8.5 1.30 31.5 4.33 5.13 35 9  
                           
12/17/2020 26.0 6.0 0.64   11           45 22 Statred around 3am.  6" fell overnight into the AM and the other 6.5" fell during ops hrs og 12/17
12/18/2020 32.0 6.5 0.60   9 12.5 1.24 44.0 5.57 6.37      
                           
12/26/2020 27.0 3.0 0.40   13           32 23 .45 on sensors
12/27/2020 28.0 1.0 0.15   15 4.0   48.0     33 22 Snow fell during PM ops hrs of 12/26.  Both precip sensors recorded .24"H2o  Windblown from trees?
                           
12/28/2020 32.0 4.5 0.24   6           20 16  
12/29/2020 31.0 3.0 0.19   6 7.5 0.43 55.5 6.00 6.80 24 15  
DEC Total   34.5 3.77                    
Date Base Depth  HN24(") SWE Rain % Density StormSnow " Storm SWE " Season Snow Season SWE Season Precip Base Hi Temp Base Lo Temp Notes
1/5/2021 30.0 2.0 0.45   23 2.0 0.45 55.5 6.45 7.25 32 23 Swing and a miss…Strike one.  Strong winds overnight at all elevations.  
                           
1/23/2021 26.0 2.0 0.08   4 2.0 0.08 57.5 6.53 7.33 22 8 Greatest snow on earth
                           
1/24/2021 26.5 1.0 0.06   6           19 8
1/25/2021 32.0 5.5 0.26   5 6.5 0.32 64.0 6.85 7.65 25 10 GSoE piling up 
                           
1/27/2021 45.0 17.5 0.90   5           16 4 If we only had a base.
1/28/2021 78.0 45.0 4.11   11           22 15 upside down cake 21" and 1.6 fell during ops hrs of 1/27
1/29/2021 97.5 30.5 2.80   9           21 17  
1/30/2021 91.0 3.0 0.12   4 96.0 7.93 162.0 14.78 15.58 20 13  
JAN Total   106.5 8.78                    
2/3/2021 76.0 0.5 0.12   24 0.5 0.12 162.5 14.90 15.70 31 23 10 feet of wind delayed opening until 10am. 1/2"Graupel
                           
2/12/2021 77.0 15.0 1.70   11 15.0 1.70 177.5 16.60 17.40 42 21 Great day of skiing, even avalanche debris.  Whole mtn opened 
Date Base Depth  HN24(") SWE Rain % Density StormSnow " Storm SWE " Season Snow Season SWE Season Precip Base Hi Temp Base Lo Temp Notes
2/14/2021 75.5 6.0 0.63   11 6.0 0.63 183.5 17.23 18.03 25 11 Most snow fell during ops hours 2/13
                           
2/16/2021   0.5 0.05 M 10 0.5 0.05 184.0 17.28 18.08 34 19  
FEB Total   22.0 2.50                    
3/9/2021 56.0 T 0.00               24 16 Upper mtn had 3' in wind deposited areas like upper dry skiers right and Huevos
3/10/2021 65.0 8.5 0.55   6           23 14 Light SW winds 
3/11/2021 67.0 5.5 0.20   4           16 7 Snow fell during ops hrs 3/10
3/12/2021 70.0 5.0 0.30   6 19.0         22 13  
3/13/2021 71.0 2.0 0.14   7 21.0 1.19 205.0 18.47 19.27 24 10 Skies cleared around sweep 3/12
                           
3/15/2021 70.5 4.5 0.49               40 19  
3/16/2021 74.0 4.5 0.38   9 9.0 0.86 214.0 19.33 20.13 19 10 snow fell during ops 3/15.  Jasco wind all night into early morning hrs
                           
3/19/2021 69.5 4.0 0.60   15           38 28  
3/20/2021 82.5 14.0 1.80   13 18.0 2.40 232.0 21.73 22.53 31 23  
Date Base Depth  HN24(") SWE Rain % Density StormSnow " Storm SWE " Season Snow Season SWE Season Precip Base Hi Temp Base Lo Temp Notes
3/23/2021 76.0 1.0 0.13   13           32 16  
3/24/2021 76.0 T 0.03     1.0 0.16 234.0 21.89 22.69 34 18 remaining precip fell after boards were cleared on 3/23
                           
3/26/2021 76.0 3.0 0.20   7 3.0 0.20 237.0 22.09 22.89 28 15 great skiing on the lower hill but a net loss with the jasco NE winds
MAR Total   52.0 4.82                    
4/14/2021 39.5 T 0.01               40 23 Graupel
4/15/2021 41.5 2.5 0.26   11 2.5 0.27 239.5 22.36 23.16 29 14 snow fell during ops hrs 4/14
                           
4/26/2021 29.0 3.0 0.30   10 3.0 0.52 242.5 22.66 23.46 26 20 Most precip fell during ops hrs 4/25. Wind deposited and stripped areas mtn wide.  (.52 from Met one and .6 from Pluvio)
April Total   5.5 0.57                    
5/21/2021 0.0 T 0.04               36 18  
5/22/2021 2.0 2.0 0.20   10           25 19 Snow fell during ops of 5/21.  Cleared late afternoon
5/23/2021 0.5 T 0.04     2.0 0.28 244.5 22.94 23.74 33 22 Snow showers during ops 5/22
May Total   2.0 0.28                    
                           
Season Totals   244.5 23.50                    
                           
Units for Base Depth, New Snow, Storm Total, and Season Snowfall are in inches. 
SWE≡Snow Water Equivalent, the amount of water produced from melting a known volume of snow.  Measured in inches of H2O.
Season Precip includes SWE and rain since October 1st.
Units for 24 Hour Base Hi Temp and Base Lo Temp are degrees Fahrenheit.
Line breaks indicate clearing between storms, despite occasional consecutive days.
All data subject to revision.
Season Precip is from Met One sensor unless otherwise noted