Flood advisory affecting San Mateo and Santa Cruz counties early Wednesday morning triggered by substantial downpours

San Mateo and Santa Cruz counties are included in a flood advisory issued by the National Weather Service on Wednesday at 2:39 a.m. The advisory is in effect until 4:45 a.m.

The NWS San Francisco CA said, “Urban area and small stream flooding caused by excessive rainfall is expected.”

“Minor flooding in low-lying and poor drainage areas,” the NWS said. “Turn around, don’t drown when encountering flooded roads. Most flood deaths occur in vehicles. Please report observed flooding to local emergency services or law enforcement and request they pass this information to the National Weather Service when you can do so safely.”

How to use a sandbag and where to get sandbags in your area:

Follow these instructions on how to use sandbags and other flood preparation tips to protect your home, and click on the links below to get sandbags in your county:

Where to get sandbags in San Mateo County

Where to get sandbags in Alameda County

Where to get sandbags in Santa Clara County

Understanding the differences between advisories, watches, and warnings

• Flash flood warning: Take action!

A flash flood warning is issued when a flash flood is imminent or occurring. If you are in a flood-prone area, move immediately to high ground. A flash flood is a sudden violent flood that can take from minutes to hours to develop. It is even possible to experience a flash flood in areas not immediately receiving rain.

• Flood warning: Take action!

A flood warning is issued when flooding is imminent or occurring.

• Flood advisory: Be aware:

A flood advisory is released when flooding is not expected to reach a severity level necessitating a warning. Nonetheless, it can still cause considerable inconvenience and, without exercising caution, potentially lead to situations that threaten life and/or property.

• Flood watch: Be prepared:

A flood watch is issued when conditions are favorable for flooding. It doesn’t guarantee that flooding will occur, but it signifies that the possibility exists.

Weathering the storm: Flood safety guidelines from the NWS

In flood-prone regions or while camping in low-lying areas, understanding and following the NWS flood safety guidelines can be a lifesaver:

Move to higher ground:

If you reside in a flood-prone region or are camping in low-lying terrain, the first step to safety is relocating to higher ground.

Adhere to evacuation orders:

When local authorities issue an evacuation order, promptly comply. Before leaving, secure your home by locking it.

Disconnect utilities and appliances:

If time permits, disconnect your utilities and appliances. This precaution minimizes electrical hazards during flooding.

Avoid basements and submerged areas:

Steer clear of basements or rooms where water has submerged electrical outlets or cords. This helps prevent electrical accidents.

Swift evacuation for your safety:

If you notice sparks or hear buzzing, crackling, snapping, or popping sounds, evacuate without delay. Do not enter water that may carry an electrical charge.

Refrain from walking in floodwaters:

Never attempt to walk through floodwaters, even if they appear shallow. Just 6 inches of fast-moving water can forcefully sweep you off your feet.

Seek high ground if trapped:

In the event you become trapped by moving water, make your way to the highest point available and contact emergency services by calling 911.

During heavy rainfall, there is a risk of flooding, especially in low-lying and flood-prone areas. Remember to never drive through water on the road, even if it seems shallow. According to the NWS, as little as 12 inches of rapidly flowing water can carry away most cars. Stay safe by being prepared and informed.

Navigating rainy roads: Safety tips for wet weather

When heavy rain strikes, safety is paramount. Equip yourself with these guidelines from the NWS to navigate wet roads and avoid hazards:

Beware of rapid water flow:

Avoid parking or walking in close proximity to culverts or drainage ditches, as the swiftly moving water during heavy rain can potentially carry you away.

Maintain safe driving distances:

Use the two-second rule to maintain a safe distance from the car in front of you and allow an extra two seconds in heavy rain.

Slow down and stay cautious:

If it is raining and the roads are wet, slow down. Take your foot off the accelerator and let your speed drop gradually. Never use the brakes suddenly because this may cause the car to skid.

Choose your lane wisely:

Stick to the middle lanes on multi-lane roads to minimize the risk of hydroplaning, as water tends to accumulate in outer lanes.

Visibility matters:

Enhance your visibility in heavy rain by activating your headlights. Be particularly vigilant for vehicles in blind spots, as rain-smeared windows can obscure them.

Watch out for slippery roads:

The first half-hour of rain is when roads are slickest due to a mix of rain, grime, and oil. Exercise heightened caution during this period.

Keep a safe distance from large vehicles:

Don’t follow large trucks or buses too closely. The spray created by their large tires reduces your vision. Take care when passing them as well; if you must pass, do so with caution.

Mind your windshield wipers:

• Overloaded wiper blades can hinder visibility. If rain severely impairs your vision, pull over and wait for conditions to improve. Seek refuge at rest areas or sheltered spots.
• If the roadside is your only option, pull off as far as possible, preferably past the end of a guard rail, and wait until the storm passes. Keep your headlights on and turn on emergency flashers to alert other drivers of your position.

In the face of heavy rain, these precautions can make a significant difference in ensuring your safety on the road. Remember to stay informed about weather conditions and heed guidance from local authorities for a secure journey.

For more weather alerts in the Bay Area, visit Weather Advisories