Prepare for flooding

Dust off your raingear, California cyclists: rain is likely this winter throughout most of California. Predictions have firmed up considerably for epic rain due to El Niño conditions beginning in December or January for Northern California.

Santa Rosa: Amgen Tour of California 2009

Didn’t I hear all this last year?

The El Niño drumbeat may be familiar to those who remember similar predictions for last winter. El Niño conditions began to develop in 2014, and early modeling suggested a possibility for heavy rain in California, which was widely reported in the popular media as a sure thing. By summer 2014, however, the conditions that generally precede a wet winter all but disappeared. That infamous high pressure ridge in the Eastern Pacific that diverts Pacific storms away from California persisted and kept the Golden State in drought conditions.

This year, however, El Niño conditions continued to build through the summer and well into autumn. The still-intensifying 2015 El Niño is now the third strongest on record, coinciding with the warmest 2015 year-to-date on record for the state of California, and the planet’s warmest month ever, which beats 2014’s record breaking warmth by nearly two degrees Fahrenheit (0.90°C).

Morning commute, take 2. Guadalupe River Trail San Jose California.   #cycling #rain #bikecommute #commute #trail #sanjose #clouds #sky #towerofpower

Higher heat means there’s more energy and more moisture in the system, which in turn increases the chances for stronger and more catastrophic storms. Most Californians don’t pay much attention to Pacific hurricanes since their only affect is typically only a few more clouds in the sky for us, but 2015 has been an insane hurricane season, with a record-setting 22 23 Category 4 or 5 Super Typhoons so far this year. This is an amazing number — the Pacific averages 12 Super Typhoons in a typical year. Furthermore, some of these typhoons are taking unprecedented tracks far north of Hawaii, with a couple of these tropical storms even approaching Alaska.

Flood Preparedness Week

Good raingear, decent fenders, and waterproof bags should handle the drizzle typical of California rainstorms. You also know I like lights when riding in darkness and in the rain.

Because California Flood Preparednesss Week ends tomorrow, let’s discuss a few other hazards you might encounter this winter.

Watch for flooded trails

  • Flooding: I’ve seen public works agencies in the area working like madmen to clear brush and other debris from culverts and streams as they prepare for El Nino. Still, we know to expect flooding in low-lying areas. Riverside bike trails are especially prone to flooding, as are some coastal areas.

    Stormwater runoff is notoriously polluted, especially with fecal coliform and E. Coli from animal and human waste. You can watch bacterial levels climb dramatically during rain at water quality reporting websites. For that reason alone, you should probably avoid biking through deep water.

    Deep water can ruin hubs and bottom brackets if you don’t disassemble and dry them completely. Even sealed cartridge bottom brackets and hubs are subject to water ingress when fully submerged. Water will also stay inside of your wheels, possibly welding spoke nipples to rim due to corrosion.

    Murky water can obscure hidden hazards. A few years ago, I flopped over my handlebars while biking across a parking lot with just a couple of inches of standing water. The water hid a deep pothole, and down I went in spite of what I thought of as a safe, slow speed. Even if you know the road is well-paved, flooding can wash away pavement, or deposit mud, branches, and rocks.

  • Power lines: Watch for downed power lines and stay away from them. PG&E distribution lines (the basic wiring you see on wooden utility poles) carry 20 thousand volts or more; a few millimeters of water rubber won’t insulate you from that.

    I’m always a little paranoid when riding trails like the Stevens Creek in Mountain View, which runs along an easement for high voltage electrical transmission towers. Those don’t typically fall over during heavy rain, however, and they’re safe from the most common cause of utility pole failure, which are reported as “Vehicle VS Structure” by emergency dispatchers.

  • Road and trail closures: The motoring public has an entire infrastructure of technology-driven media to divert them around weather-related road problems. As cyclists, we might be able to huck a bike over a fallen tree or around a minor landslide where a car might not fit, but we’re mostly on our own when we need to find detours. 2015 may be the year I finally provide a feed of Bay Area and Santa Cruz bike hazards that utilizes public data augmented by crowd provided information. In the meantime, please feel free to consult my Santa Clara County trail status web page before you begin your journey.


  1. For those who ride in glasses, like me, and are tired of getting rain all over your lenses while on rides, I have a DIY lifehack to fix that for the low low cost of a 2 liter soda bottle. This creation has been my most cherished and useful piece of rain gear, preserving my vision even in near downpour conditions (as close as California has gotten in the past five years at least).

    Check it out:

    I’ll be making a new one ASAP. My biggest issue is that I don’t drink soda that comes in 2 liter bottles anymore, so I need to find an alternate bottle to repurpose or use someone else’s soda bottle.

    I’ve also got my rain pants, bag cover, and obnoxiously bright reflective jacket ready to go.

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