Mammoth Mountain Ski Patrol Storm Summaries


1	2024-2025
2
3	Date	Base Depth	HN24(")	Man SWE	Rain	% Density	StormSnow "	Storm SWE "	Season Snow	Man Season SWE	Met OneSeason Precip	Base Hi Temp	Base Lo Temp	Notes

4	10/17/24	T	T		0.14							53	36	Precip began @ 3:30pm on 10/16. Sesame stopped reporting @18:00hrs 10/16
5	10/18/24	0	0		0.14						0.28	21	17
6
7	10/28/24	0.5	0.5	0.01		2					0.29	35	32
8	10/29/24	3	3	0.25		8	3.5	0.25	3.5	0.26	0.54	16	12
9	OCT		3.5	0.26	0.28	4			3.5	0.26	0.54
10
11	11/2/24	2	2	0.17	0	9	2	0.17	5.5	0.43	0.71	29	25
12
13	11/12/24	5	5	0.3	0	6	5	0.3	10.5	0.73	1.01	23	15	strong S-SW winds all day w/ a quick hitting snow band from the NW that started around 1600 11/11
14
15	11/15/24	4	2	0.16	0	8				0.89		37	17
16	11/16/24	7	5	0.42	0	10	7	0.58	17.5	1.31	1.59	23	16	Heavy low density snow showers @ end of ops day into evening. Light winds associated from NW. Switched to ENE in AM
17
18	11/23/24	16	11.5	1.5		13	11.5			2.81		44	26	Overnight snow fall with strong S-SW winds. Average density
19	11/24/24	20	6.5	1.1	0	17	18	3.1	35.5	3.91	4.69	30	21	Left over precip from yesterdays 05:30 measurement. Met one measurement was 1.6. Lots of whumpfing off piste
20
21	11/25/24	20	1	0.08	0	8			36.5			27	15	Definitive storm break yesterday. Early AM snow showers w/ light S winds
22	11/26/24	40	23	3.1		15	24		59.5			31	22	5.5" during ops hrs 11/25 Heavy snow over night. No change in density from ops hrs
23	11/27/24	34	6	1	0	17	25.5	4.18	65.5	8.09	8.88	28	16	Moderate wind transport overnight
24	NOV		62	7.83	0	11			65.5	8.09	8.88	30.2	19.2
25	Date	Base Depth	HN24(")	Man SWE	Rain	% Density	StormSnow "	Storm SWE "	Season Snow	Man Season SWE	Met OneSeason Precip	Base Hi Temp	Base Lo Temp	Notes
26	12/13/24	39	9	0.95	0	11						32	18	Manually measuring base depth .
27	12/14/24	41	6	0.68	0	11						28	18	Base depth? puzzling
28	12/15/24	43	4	0.4	0	10	19	2.03	84.5	10.12	11.05	25	17
29
30	12/17/24	39	1	0.2	0	20	1	0.2	85.5	10.22	11.15	37	25
31
32	12/22/24	40	3	0.5	0		3	0.5	88.5	10.72	11.57	41	29
33
34	12/25/24	47.5	9	0.95	0	10	9	0.95	97.5	11.22	12.53	36	13	snow fell during ops and sweep WSW winds picked up after ops
35
36	12/27/2024	48	3	0.5	0	17						36	26
37	12/28/2024	47	1	0.06	0	6	4	0.56	101.5	11.78	13.01	40	25	Good dense coating allowed us to open Hangmans.
38
39	12/30/2024	49	4	0.75	0	19	4	0.75	105.5	12.53	13.71	34	27	Strong winds during operating hours on 12/29.
40	DEC		40	4.49	0	13			105.5	12.53	13.71	34	22
41	Date	Base Depth	HN24(")	Man SWE	Rain	% Density	StormSnow "	Storm SWE "	Season Snow	Man Season SWE	Met OneSeason Precip	Base Hi Temp	Base Lo Temp	Notes
42	01/04/2025	50	4	0.5	0	12.5	4	4	109.5	13.03	14.2	36	15	Short period of intense snowfall
43
44	01/07/25	49	1	0.1	0	8	1	0.1	110.5	13.13	14.28	40	16	North wind event with little snow overnight
45
46	01/26/2025	48	3.5	0.25	0	7			114			26	11	Low density snow primarily falling overnight 1/25. 2F at summmit this morning. Moderate and variable winds overnight.
47	01/27/2025	48.5	1	0.05	0	5	4.5	0.25	115	13.43	14.67	17	11	Upslope winds have increased. High starting zones observed yesterday revealed stripping down to old snow surface.
48	JAN		9.5	0.9	0	8			115			30	13
49
50	02/01/2025	49	2	0.25	0.28	25					15.2	36	24	Rain snow mix overnight. Rising snow levels today then wind event Sun Mon
51	02/02/2025	50	1	0.25	0.74	25	3	0.5	118	13.93	16.19	36	32	Rained to the summit but only for a short duration. Mtn has a stout rain crust mid mtn and below. Upper mtn's crust is more edgeable
52
53	02/05/2025	58	9	2.5	0	28						34	26	widespread dense wind slab of varying thickness across mtn. Thicker slabs were reactive on rain crust
54	02/06/2025	58	0.5	0.07	0	14	9.5	2.57	127.5	16.48	18.94	31	23	snow showers in AM after obs
55
56	02/07/2025	65	9	2	0	20						31	24	Most fell during ops 2/6. Lt Rain at lower elevations below sesame
57	02/08/25	65	1	0.1	0	10	10	2.1	137.5	18.6	21.17	28	6	lingering snow showers and thick low clouds during ops 2/7. Unable to open top after mitigation work.
58
59	02/13/2025	78	15.5	1.6	0	10						32	11	Received high end of forecasted overnight snow.
60	02/14/2025	103	34	4.9	0	14						24	22	Heavy snowfall during ops hrs 02/13 18"/2.7"H2o@3:30
61	02/15/2025	103	2	0.2	0	28	51.5	6.7	189	25.3	26.46	28	21
62	Feb Totals		74	9.17	1.02	20						31	21
63	Date	Base Depth	HN24(")	Man SWE	Rain	% Density	StormSnow "	Storm SWE "	Season Snow	Man Season SWE	Met OneSeason Precip	Base Hi Temp	Base Lo Temp	Notes
64	03/02/2025	70	3	0.25		8						28	20
65	03/03/2025	75	6.5	0.6		9	9.5	0.85	198.5	26.15	27.03	28	15
66
67	03/05/2025	72	0.5	0.01		2						39	27
68	03/06/2025	80	11	1.2		11						18	13
69	03/07/2025	78	2	0.05		3	13.5	1.26	212	27.41	28.07	17	9
70
71	03/13/2025	95	22.5	2.6		12						19	16
72	03/14/2025	100	5	0.45		9						19	10
73	03/15/2025	105	6	0.6		10	33.5	3.65	245.5	31.06	31.42	21	16
74
75	03/17/2025	103	T									37	23
76	03/18/2025	113	10	1.2		12	10	1.2	255.5	32.26	32.87	26	12
77
78	3/29/2025	93	T									35	19
79	3/30/2025	94	1	0.02		1						30	20
80	3/31/25	96	6	1.15		19	7	1.17	262.5	33.43		31	22
81	MAR		91	8.13		9						27	17
82	4/1/2025	103	9.5	1.4		15						27	14	Same storm separating months
83	4/2/2025	111	8	0.7		9	24.5	3.29	280	35.53	35.84	20	8
84
85	4/26/2025	62	1	0.1		10				35.63	35.89	36	20
86	4/27/2025	63	1	0.1		10	2		282	35.73	36.04	26	20
87	APR		19.5	2.3		11						27	16
88	5/1/2025	61	0.5	0.2	0.08	40	0.5	0.2	282.5	35.93	36.32	48	30
89
90	5/3/2025	60	0	0	0.03							53	35
91	5/4/2025	55	1	0.2	0.29	20						38	31
92	5/5/2025	53	T	0.05	0.14		1	0.25	283.5	36.18	37.03	42	30
93
94	5/13/2025	28	0.5	0.1		20						42	24
95	5/14/2025	26	3	0.35		12	3.5	0.45	287	36.63	37.51	31	21
96
97
98
99	Units for Base Depth, New Snow, Storm Total, and Season Snowfall are in inches.
100	SWE≡Snow Water Equivalent, the amount of water produced from melting a known volume of snow. Measured in inches of H2O.
101	Season Precip includes SWE and rain since October 1st.
102	Units for 24 Hour Base Hi Temp and Base Lo Temp are degrees Fahrenheit.
103	Line breaks indicate clearing between storms, despite occasional consecutive days.
104	All data subject to revision.


1	2023-2024
2
3	Date	Base Depth	HN24(")	Man SWE	Met One	Pluvio	Rain	% Density	StormSnow "	Storm SWE "	Season Snow	Season SWE	Season Precip	Base Hi Temp	Base Lo Temp	Notes

4	10/1/23	0	T				0.35							54	31
5
6	10/18/23	0	T				????									Power to Sesame site was turned off for construction. Rained with a trace of snow.
7
8	10/26/23	0	T				0.13							33	29
9	OCT Total						0.48									Incomplete Data set
10	11/6/23	0	T	0.05										39	34
11	11/7/23	4.5	4.5	0.95	1.49		0.54	21			4.5			33	26	Moderate to strong SW winds. Dusting in Town rain/snow mix. Start of the snowpack for sure on N aspects
12	11/8/2023	4	T	0.02	0.02					1.02		1.02		30	20
13
14	11/16/23	4	2	0.6	0.74		0.14	30		0.6	6.5	1.62		34	31	Period of rain midday at Main Lodge. Light SSW wind
15
16	11/18/23	8	2	0.24	0.25			12			8.5		3.02	30	28	Light to Mod S winds. Poor visibility due to fog
17	11/19/23	13.5	6.5	1.13	1.24	1.2		17	8.5	1.37	15	2.99	4.15	29	22	Increasing winds overnight on 11/18, gusts over 100mph at and top of ch. 1 Decreasing temps overnight. Clear skies by 6 a.m.
18	NOV Total		15	2.99				20
19	12/1/23	12	1	0.1	0.09	0.12	0.09	10	1	0.09	16	3.09	4.25	21	19	Light snowfall mainly after 1300
20
21	12/07/23	13	2	0.41	0.39	0.4	0.01	20	2	0.41	18	3.5	4.66	40	24	Strong to extreme SSW winds. Areas with dense wind slab and others scoured to old snow or ground
22
23	12/18/23	13.5	1	0.1	0.09	0.12		10						43	30
24	12/19/2023	16.5	4	1.2	1.41	1.12	0.2	30						32	30	Periods of rain up to 9400'
25	12/20/23	19.5	3	0.45	0.65	0.51		15						30	28	Rain before snow. Dense fog
26	12/21/23	17.5	1	0.1	0.11	0.12		10	9	1.67	27	5.35		30	28
27	DEC Total		12	2.36			0.21
28	1/3/24	30	12.5	1.1	1.12	1.01		9			39.5	6.45		31	17	Heavy snow overnight. Snow starting around 11pm.
29	1/4/24	29.5	2.5	0.2	0.11	0.04		8	13	1.3	42	6.65		15	10	Light snow during the day. Winds shifting to NNE overnight. Clearing skis overnight.
30
31	1/7/2024	32	9.5	1	0.74	0.6		11	11	1	51.5	7.85		10	4	Strong to extreme S winds switching to E after Midnight. Snowfall mainly between 1500 - 2200. Coldest temps of the season.
32
33	1/11/24	37.5	14	1.85	1.04	1.01		13	14	1.85	65.5	8.89		15	8	Extreme winds yesterday. Using MetOne for Season SWE as manual measurment was affected by the wind.
34
35	1/14/24	35.5	3.5	0.6	0.37	0.52		17	3.5	0.6	69	9.49		27	24	Light snow in the AM SW winds.
36
37	1/17/2024	39	7.5	1.3	0.77	0.71		17	7.5	1.3	76.5	10.26		40	27	Extreme winds yesterday. Using MetOne for Season SWE as manual measurment was effected by the wind.
38
39	1/20/2024	42	5	0.55	0.66	0.62		11	5		81.5	10.81		27	26	Strong SW winds
40	1/21/2024	44	5.5	0.9	0.59	0.6		16	10.5	1.45	87	11.71		25	22	Scattered showers
41
42	1/22/2024	45.5	3	0.35	0.21	0.23		11	3		90	12.06		27	25	Snow today 3-5 inches possible. Light SW winds.
43	1/23/2024	50	6.5	0.7	0.7	0.67		11	9.5		96.5	12.76		28	19	Light winds and clear day.
44
45	1/25/2024	49	2	0.35	0.24	0.25		18	2	0.35	98.5	13.11		33	22	Strong SW winds
46	JAN Total		71.5	8.9
47
48	2/1/2024	54	12	1.4	1.25	1.16		12	12		110.5	14.51		27	26	Strong SW winds
49	2/2/2024	60.5	13	1.1	0.94	0.84		8	25		123.5	15.61		26	18	Strong SW winds overnight
50	2/3/2024	61	6.5	0.6	0.13	0.15		9	19	3.1	130	16.21		16	14	Snow showers overnight with gusty SW winds
51
52	2/4/2024	62	6	0.5	0.42	0.45		8	6		136	16.71		21	14	Heavy Snow and increasing SW winds
53	2/5/2024	81.5	33	4.9	3.51	3.22		7	27		169	21.61		24	20	Increasing winds overnight. Extreme SW winds. Max gust over the summit of 125mph.
54	2/6/2024	84.5	7	0.5	0.49	0.52		7	30	4.85	176	22.11		23	22	Snow showers with partly sunny conditions. Moderate S winds.
55
56	2/7/2024	81.5	1	0.06	0	0		7				22.17		20	18
57	2/8/2024	84.5	7.5	0.7	0.64	0.58		8	8.5	0.76	184.5	22.87		18	13
58
59	2/10/2024	80	1	0.1	0.04	0.05		10	1	0.1	185.5	22.91		23	8
60
61	2/15/2024	82.5	11	1.2	1.12	1.01		11	11	1.12	196.5	24.11		31	21	Extreme SW winds and high precipitation rate over night, clearing in the morning.
62
63	2/19/2024	89	10.5	1.5	1.08	1.18		14	10.5		212	26.31		35	24	Snow started around midnight. Strong SW-SE winds.
64	2/20/2024	90.5	9	1.65	1.14	0.7		18	15.5	2.8	221	27.96		29	21	Snow ended around 1800.
65
66	2/21/2024	96.5	9	0.9	0.82	0.78		10	9	0.9	230	28.86		24	20	Storm overproduced from the forecast with strong S winds overnight.
67
68	2/27/2024	84.5	1	0.15	0.1	0.14		15	1	0.15	231	29.01		28	23	Strong S winds over the summit.
69	Feb Total		132.5	15.96
70
71	3/1/2024	83	1	0.2	0.29	0.36		29			232	29.3		28	23
72	3/2/2024	101	18.5	2.9	2.71	2.59		16			250.5	32.2		25	19	Extreme SW winds, no operations
73	3/3/2024	115	17	2.65	1.72	1.54		16			267.5	34.85		20	13	Extreme SW winds, no operations
74	3/4/2024	110	2	0.25	0.16	0.13		13	38.5	6.09	269.5	35.1		18	15	Extreme SW winds and continued intense blowing snow. Study plot very wind effected.
75
76	3/12/2024	96	1.5	0.15	0.07	0.06		10			271	35.25		38	23	Snow showers began after midnight. Winds remained strong at ridgetop out of SW during operating hours. Poor visibility mid mountain and above.
77	3/13/2024	97	1	0.25	0.26	0.27		25	2.5	0.4	272	35.5		31	22	Upslope snow showers.
78
79	3/15/2024	94.5	1	0.1	0	0		10	1	0.1	273	35.6		27	19	Upslope winds continue.
80
81	3/23/2024	91.5	8	1	0.96	1		13			281	36.6		39	18	Snow showers continued throughout the day.
82	3/24/2024	97	6	0.75	0.79	0.52		13			287	37.35		25	16	Steady strong SW winds overnight. Snowshowers continued through the day.
83	3/25/2024	98	3	0.3	0.22	0.22		10	17	2.05	290	37.65		26	12	Snow showers and moderate winds during operating hours yesterday. Winds decreased and were variable overnight.
84
85	3/28/2024	100.5	12	1.65	1.68	1.68		15	12	1.65	302	39.3		37	25	All snow fell after operating hours on 3/27. Winds strong out of the S and SW at upper elevations overnight.
86
87	3/29/2024	105	4	0.6	0.8	0.69		15			306	39.9		26	19
88	3/30/2024	121.5	20	1.85	1.42	1.43		9	24	2.45	326	41.75		19	23
89
90	4/1/2024	117.5	3	0.25	0.22	0.21		8	3	0.25	329	42		27	17	Short, intense burst of snowfall between 6 p.m. and 8 p.m. after closing yesterday. Winds shifted upslope overnight at the ridgetop.
91	MAR Total		98	12.9												April 1 LADWP SnowSurvey @ Sesame: Average HS 124.5", Manual SWE 43.3"
92	4/5/2024	120	19	2	1.86	1.67		11			348	44		10	4
93	4/6/2024	123	6	0.4	0.35	0.39		7	25	2.4	354	44.4		15	9
94
95	4/8/2024	113	0.5	0.05	0.05	0.06		10	0.5	0.05	354.5	44.45		30	13	Snow showers after closing as winds began to veer upslope.
96
97	4/14/2024	100	1	0.4	0.3	0.3		40	1	0.4	355.5	44.85		37	17
98
99	4/26/2024	74	1	0.4	0.21	0.26		40	1	0.4	356.5	45.25		23	19
100	4/27/2024	73	1	0.2	0.18	0.18			2	0.5	357.5	44.45		33	23
101	APRIL total		28.5	3.45
102	5/5/2024	65	10	1.5	1.66	1.58			10	1.5	367.5	45.95		34	14
103
104
105	SWE≡Snow Water Equivalent, the amount of water produced from melting a known volume of snow. Measured in inches of H2O.
106	Season Precip includes SWE and rain since October 1st.
107	Units for 24 Hour Base Hi Temp and Base Lo Temp are degrees Fahrenheit.
108	Line breaks indicate clearing between storms, despite occasional consecutive days.
109	All data subject to revision.