气候变化领域集成服务门户(CCPortal): Debris flow magnitude, frequency, and precipitation threshold in the eastern North Cascades, Washington, USA

CCPortal

DOI	10.1007/s11069-021-04553-8
	Debris flow magnitude, frequency, and precipitation threshold in the eastern North Cascades, Washington, USA
	Riedel J.L.; Sarrantonio S.M.
发表日期	2021
ISSN	0921030X
起始页码	2519
结束页码	2544
卷号	106 期号:3
英文摘要	We examine the magnitude, frequency, and precipitation threshold of the extreme flood hazard on 37 low-order streams in the lower Stehekin River Valley on the arid eastern slope of the North Cascades. Key morphometric variables identify the magnitude of the hazard by differentiating debris flood from debris flow systems. Thirty-two debris flow systems are fed by basins < 6 km2 and deposited debris cones with slopes > 10°. Five debris flood systems have larger drainage areas and debris fans with slopes 7–10°. The debris flood systems have Melton ruggedness ratios from 0.42–0.64 compared to 0.78–3.80 for debris flow basins. We record stratigraphy at seven sites where soil surfaces buried by successive debris flows limit the age of events spanning 6000 years. Eighteen radiocarbon ages from the soils are the basis for estimates of a 200 to1500-year range in recurrence interval for larger debris flows and a 450 ± 50-year average. Smaller events occur approximately every 100 years. Fifteen debris flows occurred in nine drainage systems in the last 15 years, including multiple flows on three streams. Summer storms in 2010 and 2013 with peak rainfall intensities of 7–9 mm/h sustained for 8–11 h triggered all but one flow; the fall 2015 event on Canyon Creek occurred after 170 mm of rain in 78 h. A direct link between fires and debris flows is unclear because several recent debris flows occurred in basins that did not burn or burned at low intensity, and basins that burned at high intensity did not carry debris flows. All but one of the recent flows and fires occurred on the valley’s southwest-facing wall. We conclude that fires and debris flows are linked by aspect at the landscape scale, where the sunny valley wall has flashy runoff due to sparse vegetation from frequent fires. © 2021, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.
关键词	Cascades Debris flow hazard Frequency Precipitation threshold
英文关键词	debris flow; hazard assessment; precipitation (climatology); precipitation intensity; rainfall; runoff; soil surface; threshold; Cascade Range; United States; Washington [United States]
语种	英语
来源期刊	Natural Hazards
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/206523
作者单位	U.S. National Park Service, Marblemount, United States
推荐引用方式 GB/T 7714	Riedel J.L.,Sarrantonio S.M.. Debris flow magnitude, frequency, and precipitation threshold in the eastern North Cascades, Washington, USA[J],2021,106(3).
APA	Riedel J.L.,&Sarrantonio S.M..(2021).Debris flow magnitude, frequency, and precipitation threshold in the eastern North Cascades, Washington, USA.Natural Hazards,106(3).
MLA	Riedel J.L.,et al."Debris flow magnitude, frequency, and precipitation threshold in the eastern North Cascades, Washington, USA".Natural Hazards 106.3(2021).