MOUNT RAINIER
GEOLOGY & WEATHER
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Possible September 5 Muir Snowfield Outburst Flood

Known Geologic Events at Mount Rainier

The purpose of this page is to list all known, dated gelogic events at Mount Rainier, including lahars, debris flows, large rockfalls, large avalanches, rockfalls, and other events. This list is currently being compiled, so if you find errors or a missing event, please let Scott know.

Database ID#: 158
Date: Sunday, September 5, 2021
Location: Muir Snowfield
Glacier Name: Muir Snowfield
Drainage Basin: Nisqually River/Pebble Creek, POSSBILY also in Stevens Creek
Event Type: Unknown

Weather:
Paradise: High 63.6, Low 49.4, 0 rain
Muir: High 45.4, Low 38.2.
DFH: Low - https://dfh.morageology.com/view_dfh.php?d=2021-09-05

Season: Dry

Notes:
Reported on Facebook Group Ashford Heads Up by Andy Carey: "Looks like we might have had a mini-Jokulhlaup--yesterday the outflow from Pebble Creek resembled an urban storm drain during a thunderstorm, the river rose and the water was muddy, suggesting some ice dam on the Muir Snowfield burst, letting the backed up waters rush out. Today there was just a trickle at the creek." On followup, Carey stated: "We did see the outpouring at Pebble Creek yesterday--we had never seen so much water shooting out so far! We also noticed the change in water color and sediment load on the reach near Nisqually Park; it is still muddy today." Carey did not get any photos or videos of the event. Estimated approximate time was 12:30 PM.

Nisqually River at Longmire shows a decrease in river conductivity (12.78 us to 8.28 from 14:15 to 18:45), but a normal change in diurnal temps. No turbidity meter in place.

Seth @ USGS regarding infrasound/seismic: "nothing obvious. the infrasound (EDF) stayed elevated for a couple of days after, which could be from the additional flow out of pebble creek, or the wind. not sure which. but I see no outburst."

Followup to this event on 9/16/2021... from an email by Kyle Nelson, LE Ranger at the park: "on the 4th I drove across Stevens Creek and it was the same color as the Nisqually. Surprised me since if often has some color from silt but not dark chocolate. Water level did not appear to be up any but the color caught my attention." also "observation would have been between 1400-1500 hrs." Stevens Creek would be sort of the opposite direction of Pebble Creek, but has a very similar source area... also there's a discrepancy in the date between the 4th and the 5th.

Geology/Imminent Threat staff member Taylor Kenyon looked at the Pebble Creek area a few days after and didn't observe anything that looked obvious. Photos are on the network drive.

*** THIS EVENT IS NOT A CONFIRMED OUTBURST FLOOD, BUT A POSSIBLE EVENT ***

Estimated Velocity:
Estimated Peak Flow:
Estimated Volume:

References:
Andy Carey, personal communication, 2021 Kyle Nelson, personal communication, 2021



Data references:

Beason, S.R., 2012, Small glacial outburst flood occurs on Mount Rainier - October 27, 2012: Unpublished National Park Service Science Brief, 3 p.
Beason, S.R., et al., in prep, Glacial outburst floods and debris flows from the South Tahoma Glacier, Mount Rainier National Park, Washington: August and September, 2015: National Park Service Natural Resource Report NPS/MORA/NRR-2015/XXX.
Copeland, E.A., 2010, Recent periglacial debris flows from Mount Rainier, Washington: M.S. Thesis, Oregon State University, 125 p.
Copeland, E.A., P.M. Kennard, A.W. Nolin, S.T. Lanscaster and G.E. Grant, 2008, Initiation of recent debris flows on Mount Rainier, Washington: A climate warming signal? American Geophysical Union Fall Meeting, San Francisco, CA.
Crandell, D.R., 1971, Postglacial lahars from Mt. Rainier volcano, Washington: U.S. Geological Survey Professional Paper 677, 75 p.
Donovan, K.H.M, 2005, An investigation into the 2003 Van Trump Creek debris flow, Mt. Rainier, Washington, United States of America: BSc Geological Hazards Thesis, University of Portsmouth (UK), 58 p.
Driedger, C.L. and A.G. Fountain, 1989, Glacier outburst floods at Mout Rainier, Washington State, USA: Anals of Glaciology, Vol. 13, 5 p.
Hodge, S., 1972, The movement and basal conditions of the Nisqually Glacier, Mount Rainier: Ph.D Thesis, Univeristy of Washington, xxx p.
Legg, N.T., 2013, Debris flows in glaciated catchments: A case study on Mount Rainier, Washington: M.S. Thesis, Oregon State University, 162 p.
Legg, N.T., A.J. Meigs, G.E. Grant and P.M. Kennard, 2014, Debris flow initiation in proglacial gullies on Mount Rainier, Washington: Geomorphology, Vol. 226, p. 249-260.
Richardson D., 1968, Glacier outburst floods in the Pacific Northwest: U.S. Geological Survey Professional Paper 600-D, D79-D86.
Samora, B., 1991, Chronology of flood events as noted in the superintendent's annual reports 1940-1991, Unpublished Internal Document, Mount Rainier National Park, WA, 13 p.
Scott, K.M., J.W. Vallance, and P.T. Pringle, 1995, Sedimentology, behavior, and hazards of debris flows at Mount Rainier, Washington: United States Geological Survey Professional Paper 1547, 56 p.
Vallance, J.W., C.L. Driedger and W.E. Scott, 2002, Diversion of meltwater from Kautz Glacier initiates small debris flows near Van Trump Park, Mount Rainier, Washington: Washington Geology, Vol. 30, No. 1/2, p. 17-19.
Vallance, J.W., M.L. Cunico and S.P. Schilling, 2003, Debris-flow hazards caused by hydrologic events at Mount Rainier, Washington: United States Geological Survey Open-File Report 2003-368, 4 p.
Walder, J.S. and C.L. Driedger, 1994, Geomorphic changed caused by outburst floods and debris flows at Mount Rainier, Washington, with emphasis on Tahoma Creek valley: U.S. Geological Survey Water-Resources Investigations Report 93-4093, 100 p.
Walder, J.S. and C.L. Driedger, 1994, Rapid geomorphic change caused by glacial outburst floods and debris flows along Tahoma Creek, Mount Rainier, Washington, USA: Arctic and Alpine Research, Vol. 26, No. 4, p. 319-327.
Walder, J.S. and C.L. Driedger, 1995, Frequent outburst floods from South Tahoma Glacier, Mount Rainier, USA: relation to debris flows, meterological origin and implications for subglacial hydrology: Journal of Glaciology, Vol. 41, No. 137, 11 p.