At 5:29 a.m. Friday, the National Weather Service issued a flood warning for the Hudson, Essex and Union coastal counties, effective from 8 p.m. to 2 a.m. Saturday.

The weather service comments: “If you must travel, allow extra time as some roads may be closed. Do not drive around roadblocks or through waters of unknown depth. Take necessary measures to protect buildings at risk of flooding.”

Deciphering advisories, observations and warnings: Understanding weather warnings

• Flash flood warning: take action!

A flash flood warning is issued when a flash flood is imminent or is already occurring. In areas at risk of flooding, it is important to get to higher ground immediately. A flash flood is a sudden and severe flood that can develop within minutes to hours and can occur even in areas where there is currently no rainfall.

• Flood warning: take action!

A flood warning is issued when flooding is imminent or already underway.

• Flood warning: Please note:

A Flood Warning is issued when flooding is not expected to be severe enough to warrant a warning, but may cause significant inconvenience and, if care is not taken, may result in situations which may threaten life and/or property.

• Flood warning: Be prepared:

A flood warning is issued when conditions are favourable for flooding. It does not guarantee that flooding will occur, but indicates that the possibility exists.

Weather Service Flood Safety Guidelines: Weathering the Storm

In flood-prone regions or when camping in low-lying areas, understanding and following the weather service’s flood safety guidelines can be life-saving:

Move to higher ground:

If you live in a flood-prone area or are camping in low-lying areas, the first step to safety is to move to higher ground.

Follow the evacuation instructions:

If local authorities issue an evacuation order, obey it immediately. Secure your home by locking it before leaving.

Disconnect utilities and equipment:

If time permits, unplug your utilities and appliances. This will reduce the risk of electrical hazards during flooding.

Avoid flooded basements and flooded areas:

Avoid basements or rooms where sockets or cables are under water. This way you can avoid electrical accidents.

For safety reasons, evacuate immediately:

If you notice sparks or hear buzzing, crackling, popping or banging noises, evacuate immediately. Do not enter water that may be live.

Stay away from floods:

Never attempt to walk through flood water, even if it appears shallow. Even 6 inches of fast-flowing water can sweep you off your feet with full force.

If you are trapped, seek higher ground:

If you become trapped in running water, go to the highest possible point and call 911.

Heavy rain can cause flooding, especially in low-lying and flood-prone areas. Never attempt to drive through water on the road, no matter how deep it appears. According to the weather service, as little as 30 cm of water can sweep away most vehicles. Be sure to stay safe by being informed and prepared.

Advance Local Weather Alerts is a service from United Robots that uses machine learning to compile the latest data from the National Weather Service.