Snowpack Prediction Revisited: Flood Risk Remains
A year ago, our team highlighted the powerful December 2021 storm system along the West Coast as it dropped heavy snow in the mountains of the Sierra Nevada, and the Cascade Range (Leonard, 2021).
The storm systems were excellent news for the drought-plagued region and its struggling mountain snowpack; without it, a resulting decrease in the extent of alpine tundra ecosystems could threaten some species. (EPA, 2016).
Fast forward to January 2023, and the Sierra snowpack has ballooned to more than double its usual size for this time of year! “A flurry of storms unloaded historic amounts of rain and snow across California over the past month. The deluges, fueled by a parade of atmospheric rivers, filled reservoirs and have improved drought conditions across large swaths of the state” (Lee, 2023). The snow will continue to replenish California’s water supplies as it melts during the warmer months. This is great news for the environment, however, just as we pointed out a year ago, this does bring increased risk for property owners in California. The storm could disrupt travel and damage buildings due to potential flooding. The replenished snowpack sets the stage for potential “flood issues as we move through the snowmelt season, said Michael Anderson, state climatologist with the California Department of Water Resources, at a media briefing on Jan. 16″ (Lee, 2023). Rain falling on snow, in particular, can cause a rapid melt that overwhelms downstream rivers and reservoirs” (Lee, 2023).
It’s Over, Right?
Historically, immense snowfalls in the mountains of the Western United States can cause more flooding in Mexico, Baja California, Arizona, and New Mexico in the spring and summer following winter storms, like in the 1862 flood “that killed thousands, wiped out mines and ranches, and submerged the state capital” (Becker, 2018). This event was capped by a warm intense storm that melted the high snow load, and the resulting snow-melt flood was disastrous (Becker, 2018).
Risk Management Techniques
Reach out to us (email@example.com) for help with your flood control systems. Flood vents, floodplain management, and wind mitigation are all vital aspects of a risk control strategy for climate risk.
A flood vents are a useful guard against the buildup of excess moisture or water which are not healthy for structures to endure. They are permanent openings in walls that allow for the free passage of water. Flood Vents protect houses and buildings during floods by preventing hydrostatic pressure buildup that can destroy walls and foundations. This mitigation technique, allows floodwater to freely flow through an enclosure such as a crawlspace or garage (FAQs SmartVent).
Characteristics of effective flood vents:
- Free passage of water flows automatically in both directions without human intervention
- Minimum of two openings
- No higher than one foot above grade
Flood vents are useful for allowing for the automatic entry and exit of flood waters for an at-risk property. It is a “wet floodproofing” technique is required for residential buildings. Commercial buildings have the option to wet floodproof, which can be more cost-effective compared to dry floodproofing (FAQs SmartVent). Dry floodproofing includes measures that make a structure watertight below the level that needs flood protection to prevent floodwaters from entering. This type of floodproofing is often used to protect non-residential structures, water supplies, and sewage systems (FEMA).
Mitigation + Floodplain Management:
Further, property owners should also transfer risk to an insurer.
- Purchase flood insurance
- Look into Flood Hazard Areas (SFHA)
- Look for Flood Insurance Route Maps (FIRM) near your area
Becker, R. (2018, May 26). The hardest part of preparing for disasters is overcoming human nature. The Verge. Retrieved February 15, 2023, from https://www.theverge.com/2018/5/26/17321100/the-big-ones-natural-disasters-lucy-jones-earthquakes-hurricanes-volcanoes-floods
EPA – What climate change means for California. (2016, August). Retrieved December 17, 2021, from <https://www.epa.gov/sites/production/files/2016-09/documents/climate-change-ca.pdf>
FAQs. SmartVent. (n.d.). Retrieved December 17, 2021, from <https://smartvent.com/resources/faq>
FEMA: Dry Floodproofing. Dry floodproofing. (n.d.). Retrieved December 17, 2021, from <https://emilms.fema.gov/IS321/HM0103040text.html>
Lee, J. (2023, February 1). California’s snowpack may face an emerging risk that scientists are just discovering. San Francisco Chronicle. Retrieved February 10, 2023, from https://www.sfchronicle.com/weather/article/california-snowpack-wildfire-17747578.php#:~:text=The%20new%20study%20reported%20that,and%20the%20Desert%20Research%20Institute.
Leonard, D. (2021, December 13). Storm blasting California with massive mountain snow and flooding rain. The Washington Post. Retrieved December 17, 2021, from <https://www.washingtonpost.com/weather/2021/12/13/california-rain-snow-atmospheric-river
Wikimedia Foundation. (2023, January 29). Great flood of 1862. Wikipedia. Retrieved February 15, 2023, from https://en.wikipedia.org/wiki/Great_Flood_of_1862#cite_note-Verge_2018_story-5