Winter often brings severe weather to the mountains. This starts as long periods of rain and snow. The major challenges are:
- Very long power outages
- Getting trapped because roads are blocked or washed out
- Damage to houses or property from falling trees
After enough days of rain snow, mudslides and floods have historically caused both property loss and almost all the disaster related fatalities in our area.
As always, for information on basic preparedness steps for your home and family click here.
SEVERE RAIN AND SNOW
ELECTRICITY: When we get a lot of rain, the first challenge is that the power goes out. In severe storm episodes you have to be prepared for going for a week or two without electricity. Having a generator is useful, but keep in mind, that you have to be able to get fuel for the generator. And if you are using a propane fueled generator, the propane companies in winter will become backed up with orders, and may have trouble getting to your tank. So you need to have a strategy for how you will have electricity for prolonged periods of time. In situations like this, hybrid systems that combine solar power, batteries with a generator can be very useful. At minimum, you need to closely monitor the fuel consumption AND oil consumption of your generator. Also, don't particularly trust PGE's status updates, the fixes often take much longer than they confess to!
BLOCKED ROADS: Once the rain persists for many weeks, the ground becomes soggy, and wash outs on the roads become common. In addition, high winds will knock down trees and powerlines on the roads. You may become trapped at home if your own driveway is blocked and you can't get it open. Even if you can get out, you'll need to plan ahead as to how to get down from the mountain to your destination, as the status of roads frequently changes, often hourly.
- Avoid travel if you don't have to. Keep in mind, if you get down, you might not be able to come back up easily!
- Official sources (like Caltrans) are often wrong about roads being open/closed. The mailing lists will tell you what is to be trusted in your area at any given time.
- Each county has information on road closures, maintenance, repair, sand bags. See the Roads page!
- Keep your car reasonably filled up/charged.
- Carry food/water/flash lights/rain poncho with you in the car
- Have a plan for your pets if you get stuck down the hill
- Keep one month extra medication supply on hand
Blocked roads are often caused by the poorly maintained culverts in our roads. Once a strong rain happens, the culverts block, and the road washes away. This can cause severe inconvenience as residents need to make long detours for months while the roads are repaired. The key thing is to watch for and report blocked culverts
SNOW: Snow is mostly like rain, except that the roads are by definition impassible until they get plowed, and even then are very slippery, given that Caltrans has no salt up here. Be extra careful when driving in snow, use chains if it's at all doubtful! Large amounts of snow are very rare up here, and our trees are not set up for them, so expect catastrophic breakage of tree limbs. Besides messing up your property, this will exacerbate road blockages and power outages. But snow happens often enough that you should keep a snow shovel on hand.
While all thunderstorms are dangerous, the National Weather Service (NWS) defines a severe thunderstorm as one that meets at least one of the following conditions:
- Produces hail at least ¾ inch in diameter.
- Has winds of 58 miles per hour or greater.
- Produces a tornado.
The risks associated with severe thunderstorms include:
- Lightning caused fires
- Downed trees and blocked roads
- Down bursts and straight-line winds
- Hail -- Pets and livestock are particularly vulnerable to hail
- Flash floods
What to do if caught in a severe thunderstorm:
- Avoid water sources
- Avoid contact with metal surfaces
- Avoid storm-damaged areas
- Avoid flooded roadways
- Avoid using the telephone. Cell phones are considered safe to use indoors, though there is some risk when used outdoors during a storm.
- Watch for fallen power lines and trees
- Do not lie flat on the ground
- Seek shelter in a substantial, permanent, enclosed structure.
- Avoid unprotected shelters. If there are no permanent shelters within reach, take shelter in a car. Pull safely to the side of the road.
- Keep all windows closed and do not touch anything that is metal. If in the woods, find an area that is protected by low trees (not a single tall tree in the open). As a last resort, go to a low-lying area, away from trees, poles and metal objects. Squat low to the ground and place your hands on your knees with your head between them. Make as small a target as possible.
- Avoid natural lightning rods, such as trees, golf clubs, tractors, fishing rods and camping equipment.
Rule number one is to move quickly to higher ground. Flood waters can carry debris, scour soil and asphalt, and trigger landslides. Even shallow-depth, fast-moving waters of 24 inches can produce enough force to carry away a vehicle, and 6 inches of swiftly moving water can knock someone off his or her feet.
If you must evacuate:
- Take your Disasters Supplies Kit
- Refer to your Evacuation Plan
- Do not walk, swim or drive through floodwaters. Learn and practice driving the local evacuation routes.
- Stay off bridges over fast-moving water. Fast-moving water can wash bridges away without warning, especially if the water contains heavy debris.
- Keep away from waterways. If you are driving and come upon rapidly rising waters, turn around and find another route. Move to higher ground away from rivers, streams and creeks.
- Pay attention to barricades. Local responders and neighbors may place barricades to warn of flooding ahead or to direct traffic safely out of the area. Never drive around barricades.
- Avoid storm drains and irrigation ditches. During a flood, storm drains and irrigation ditches fill quickly with fast-moving water. Walking in or near storm drains or irrigation ditches is nearly a sure way to drown.
- Keep your family together.
- Precautions to follow after a flood:
- Stay out of flooded areas. Flooded areas remain unsafe. Entering a flooded area places you, and the individuals who may need to rescue you, at risk.
- Reserve the telephone for emergencies only. A non-emergency call may prevent an emergency call from getting through. It is best not to use the phone unless absolutely necessary.
- Avoid driving, except in emergencies. Reserve the roads for those who must evacuate and for emergency vehicles.
- Wait for authorities to issue a clear message that it is safe to return to evacuated areas.
- Be aware that snakes and other animals may be in your house in the aftermath of a flood. Look for boards and dark spaces and investigate with care.
- For more information on storms, floods, mudslides and other disasters, see the following links:
LANDSLIDES AND MUD FLOWS
Landslides tend to worsen the effects of flooding that often accompany them. In areas that have been burned by forest and brush fires, a lower threshold of precipitation may initiate landslides. While some landslides move slowly and cause damage gradually, others move so rapidly that they can destroy property and take lives suddenly and unexpectedly.
Areas that are generally prone to landslides include:
- Existing old landslides
- The bases of steep slopes
- The bases of drainage channels
- Developed hillsides where leach-field septic systems are used.
- Debris flows – sometimes referred to as mud slides, mud flows, layers, or debris avalanches are common types of fast-moving landslides. Flows usually start on steep hillsides as shallow landslides that accelerate to speeds that are typically about 10 miles per hour, but can exceed 35 miles per hours. The consistency of debris flows range from watery mud to thick, rocky mud that can carry away items such as boulders, trees and cars. When the flows reach flatter ground, the debris spreads over a broad area.
Be prepared for a landslide:
- Familiarize yourself with the land around you. Knowing the land can help you assess your risk
- Watch for patterns of storm water drainage on slopes near your home and especially the places where runoff water converges, increasing flow over soil covered slopes. Watch the hillsides around your home for any signs of land movement, such as small landslides or debris flows, or progressively tilting trees. Noticing small changes could alert you to an increased threat of a landslide.
- Discuss landslides and debris flows with members of your family.
- Be aware that, generally landslide insurance is not available; however in some cases, debris flow damage may be covered by flood insurance policies from the National Flood Insurance Program (www.fema.gov/nfip).
- For more information on storms, floods, mudslides and other disasters go to www.ready.gov.
- To learn more about landslides in and around the Central Santa Cruz Mountains (Love Creek, Loma Mar, Deer Borne Park, La Honda and more) watch the video below.