Mammoth Mountain Ski Patrol 2012-13 Storm Summary - Sesame Snow Study Site 9,000' (2,743m)
Date	New Snow	Base Depth	SWE	Rain	% Density	Storm Snow	Storm Precip	Season Snow	Season SWE	Season Precip	Base Hi Temp	Base Lo Temp	Notes
10/12/2012	2.5	2.5	0.47		19	2.5	0.47	2.5	0.47	0.47			No total depth sensor.
10/13/2012	0.5	~2.5	0.11		16	3.0	0.58	3.0	0.58	0.58
10/22/2012	8.0	8.0	1.06		13	8.0	1.06	11.0	1.64	1.64	44	25
10/23/2012	9.0	unknown	1.55		17	17.0	2.61	20.0	3.19	3.19	28	22
10/24/2012	Trace	unknown	0.05		-	17.0	2.66	20.0	3.24	3.24
10/25/2012	Trace	unknown	0.05		-	17.0	2.71	20.0	3.29	3.29
OCT	20.0
11/2/2012	Trace	~6.0	0.06		-	Trace	0.06	20.0	3.35	3.35	40	25
11/9/2012	5.5	11.0	0.44		8	5.5	0.44	25.5	3.79	3.79	34	12	Total depth sensor online.  Opening day 11/8/12.
11/10/2012	7.0	13.0	0.52		7	12.5	0.96	32.5	4.31	4.31	15	11	Cornice Bowl open to public.
11/16/2012	5.0	12.0	0.50		10	5.0	0.50	37.5	4.81	4.81	46	28
11/17/2012	3.5	15.5	0.45		13	8.5	0.95	41.0	5.26	5.26
11/18/2012	12.5	26.5	2.21		18	21.0	3.16	53.5	7.47	7.47	31	27	Thick melt-freeze layer on new snow board.
11/19/2012	1.0	26.5	0.25		23	22.0	3.41	54.5	7.72	7.72	29	26
11/21/2012	Trace	24.0	0.01		-	Trace	0.01	54.5	7.73	7.73	36	28
11/22/2012	0.0	22.0		0.18	-	Trace	0.19	54.5	7.73	7.91	38	27	Rain to at least 10,400' (top of chair 5).
11/29/2012	8.0	29.0	1.51		19	8.0	1.51	62.5	9.24	9.42	34	27	Thin melt-freeze crust on top of new snow
11/30/2012	12.0	40.5	2.00		17	20.0	3.51	74.5	11.24	11.42	31	26
NOV	54.5
12/1/2012	20.0	55.5	2.65	0.65	16	40.0	6.81	94.5	13.98	14.72	30	27	Mixed rain and snow.
12/2/2012	2.0	54.0	0.35	0.57	43	42.0	7.73	96.5	14.24	15.64	33	27	Mixed rain and snow.
12/3/2012	12.0	62.0	2.72	0.25	25	54.0	10.70	108.5	16.96	18.61	35	28	Mixed rain and snow.
Date	New Snow	Base Depth	SWE	Rain	% Density	Storm Snow	Storm Precip	Season Snow	Season SWE	Season Precip	Base Hi Temp	Base Lo Temp	Notes
12/6/2012	2.0	57.5	0.35	0.05	17	2.0	0.35	110.5	17.31	19.01	37	27	Wet snow until 14:45, then light rain to ~9500'.  Thin rain crust on top of new snow.  Thick MF ice crust on new snow board.
12/12/2012	Trace	53.0	0.00		-	Trace	0.00	110.5	17.31	19.01	22	40
12/13/2012	16.0	68.5	1.29		8	16.0	1.29	126.5	18.60	20.30	23	16	Widespread natural avalanche activity before and during control work.
12/14/2012	Trace	66.0	0.00		-	Trace	0.01	126.5	18.60	20.30	24	7
12/15/2012	Trace	63.0	0.01		-	Trace	0.01	126.5	18.61	20.31	17	7
12/16/2012	Trace	62.0	0.01		-	Trace	0.01	126.5	18.62	20.32	27	8
12/17/2012	3.0	62.0	0.55		19	3.0	0.56	129.5	19.17	20.87	30	24	Strong SW wind.  Extensive snow transport.
12/18/2012	16.0	75.0	2.60		16	19.0	3.16	145.5	21.77	23.47	27	20
12/19/2012	3.0	75.0	0.20		7	22.0	3.36	148.5	21.97	23.67	19	-1	Moderate NE wind.
12/22/2012	7.0	76.0	0.40		6	7.0	0.40	155.5	22.37	24.07	28	17	Increasing precipitation
12/23/2012	16.0	89.0	2.36		14	23.0	2.76	171.5	24.73	26.43	25	17	Most of the snow was yesterday. Only 3.4 overnight since cleared at 4:15pm
12/24/2012	15.5	102.5	2.23		14	38.5	4.99	187.0	26.96	28.66	26	19
12/26/2012	18.5	113.0	1.75		9	18.5	1.75	205.5	28.71	30.41	33	17
12/27/2012	10.5	114.0	0.90		9	29.0	2.65	216.0	29.61	31.31	18	9	Some wind blown snow at the plot
12/29/2012	3.0	107.5	0.10		3	3.0	0.10	219.0	29.71	31.41	22	9	Very light dry snow.
12/30/2012	1.5	107.5	0.05		3	4.5	0.15	220.5	29.76	31.46	18	5
12/31/2012	0.5	105.0	0.04		6	5.0	0.19	221.0	29.80	31.50	27	5	Top opened for a short period 12/30 PM, but storm didn't really clear until evening.
DEC	146.5
Date	New Snow	Base Depth	SWE	Rain	% Density	Storm Snow	Storm Precip	Season Snow	Season SWE	Season Precip	Base Hi Temp	Base Lo Temp	Notes
1/6/2013	2.5	99.0	0.15		6	2.5	0.15	223.5	29.95	31.65	36	15
1/7/2013	1.0	98.0	0.07		6	3.5	0.22	224.5	30.02	31.72	18	13	Top opened with poor visibility 1/6, but the storm did not actually clear until the early hours of 1/7.
1/10/2013	7.5	101.5	0.69		10	7.5	0.69	232.0	30.71	32.41	39	9
1/12/2013	0.5	97.0	0.04		6	0.5	0.04	232.5	30.75	32.45	13	-4
1/24/2013	5.0	93.5	0.60		12	5.0	0.60	237.5	31.35	33.05	39	29	Avalanche mitigation was performed on the upper mtn, but it was not opened due to poor visibility.
1/25/2013	2.0	94.0	0.40		23	7.0	1.00	239.5	31.75	33.45	36	29
1/27/2013	5.0	97.5	0.68		13	5.0	0.68	244.5	32.43	34.13	34	15	Top opened around noon, poor visibility with light snow in the morning
1/28/2013	1.5	97.0	0.10		7	6.5	0.78	246.0	32.53	34.23	18	0
JAN	25.0
2/8/2013	2.5	92.0	0.14		6	2.5	0.14	248.5	32.67	34.37	28	10
2/9/2013	1.5	91.5	0.09		6	4.0	0.23	250.0	32.76	34.46	17	8	Top opened on 2/8/13 with a high ceiling and intermittent light snow during the day
2/11/2013	0.5	91.5	0.01		4	0.5	0.01	250.5	32.77	34.47	22	9
2/20/2013	5.0	94.0	0.27		5	5.0	0.27	255.5	33.04	34.74	20	13
FEB	9.5
Date	New Snow	Base Depth	SWE	Rain	% Density	Storm Snow	Storm Precip	Season Snow	Season SWE	Season Precip	Base Hi Temp	Base Lo Temp	Notes
3/3/2013	2.0	85.5	0.32		15	2.0	0.32	257.5	33.36	35.06	43	26
3/4/2013	3.5	90.0	0.42		13	5.5	0.74	261.0	33.78	35.48	29	17	Moderate N wind after 3/3 PM clearing.
3/6/2013	5.0	91.0	0.57		11	5.0	0.57	266.0	34.35	36.05	35	20	Graupel at 7am.
3/7/2013	3.0	94.0	0.30		11	8.0	0.87	269.0	34.65	36.35	22	19
3/8/2013	7.5	100.0	0.60		8	15.5	1.47	276.5	35.25	36.95	23	14
3/9/2013	2.5	103.0	0.23		9	18.0	1.70	279.0	35.48	37.18	28	17	Strong NE wind scoured the upper mountain.
3/19/2013	0.5	83.5	0.05		13	0.5	0.05	279.5	35.53	37.23	42	28
3/20/2013	1.0	82.0	0.11		11	1.0	0.11	280.5	35.64	37.34	40	26	Snow depth at plot highly variable due to wind. Sensor data used rather than manual to account for the variability in manual data.
3/21/2013	1.0	85.0	0.26		25	2.0	0.37	281.5	35.90	37.60	32	27	Melt-freeze snow.  Ice crust on board.
3/31/2013	3.5	73.0	0.40		11	3.5	0.40	285.0	36.30	38.00	47	27	Lightning in early AM before opening.
Mar	29.5
4/1/2013	4.5	78.0	0.41		9	8.0	0.81	289.5	36.71	38.41	33	23	Trace snow fell afternoon 3/31 and melted on board, causing slight ice crust.
4/5/2013	1.0	71.0	0.14		14	1.0	0.14	290.5	36.85	38.55	35	28	Due to warm temps, snow on the board melted, then refroze.  New snow depth determined by base depth increase.
4/8/2013	3.0	69.0	0.25		9	3.0	0.25	293.5	37.10	38.80	42	19
4/9/2013	0.5	69.5	0.05		11	0.5	0.05	294.0	37.15	38.85	26	15
4/16/2013	2.0	57.0	0.10		5	2.0	0.10	296.0	37.25	38.95	31	15
4/17/2013	3.0	59.5	0.22		7	5.0	0.32	299.0	37.47	39.17	22	13	Thin melt-freeze crust on the board from 4/16 AM snow.
Apr	14.0
5/5/2013	Trace	16.5	0.05		-	Trace	0.05	299.0	37.52	39.22	49	29
5/7/2013	2.5	21.5	0.32		18	2.5	0.32	301.5	37.84	39.54	34	27	Snow throughout the day but no accumualtion due to warm weather.
5/8/2013	Trace	18.5	0.05		-	2.5	0.37	301.5	37.89	39.59	36	29
5/9/2013	Trace	18.0	0.16		-	Trace	0.16	301.5	38.05	39.75	45	30
5/10/2013	0.0	16.5	0.00	0.01	-	0.0	0.01	301.5	38.05	39.76	51	34	Rain
5/16/2013	0.0	1.0	0.00	0.01	-	0.0	0.01	301.5	38.05	39.77	51	38	Rain
5/17/2013	Trace	1.0	0.05		-	Trace	0.05	301.5	38.10	39.82	42	31
5/22/2013	0.0	0.0	0.00	0.01	-	0.0	0.01	301.5	38.10	39.83	51	35	Rain
May	2.5
All observations are made in the morning, therefore all measurements are for approximately the previous 24 hours.
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.