Update: The current flood advisory for Boulder County will be expiring at 9 p.m.

Published Aug 11, 2025

The advisory had been issued for Boulder County.

“The Flood Advisory will expire at 9 p.m. this evening for a portion of northeast Colorado, including the following area, Boulder. Flooding is no longer expected to pose a threat. Please continue to heed any remaining closures,” states the National Weather Service.

Deciphering advisories, watches, and warnings: Understanding weather alerts

• 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 declared when flooding is on the verge of happening or is already underway.

• Flood advisory: Be aware:

A flood advisory is issued when flooding is not expected to be bad enough to issue a warning. However, it may cause significant inconvenience, and if caution is not exercised, it could lead to situations that may 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.

Keeping safe during floods: Expert advice 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’re in a flood-prone area, or if you’re camping in a low-lying spot, move to higher ground as a first step.

Follow evacuation orders:

If local authorities issue an evacuation order, heed it promptly. Prior to 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:

Avoid basements or rooms submerged in water with electrical outlets or cords. Preventing electrical accidents is crucial.

Evacuate promptly for 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 higher ground when 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.

When heavy rain occurs, there is a potential for flooding, particularly in areas that are low-lying or prone to floods. It is crucial to never drive through water on the road, even if it appears shallow. According to the NWS, as little as 12 inches of fast-flowing water can carry away most vehicles. Stay safe by being prepared and informed.

Navigating heavy rain: Essential safety measures for wet roads

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

Beware of swollen waterways:

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:

The two-second rule for following distance is your ally in heavy rain. Extend it to four seconds to ensure safe spacing in adverse conditions.

Slow down and stay cautious:

On wet roads, slowing down is paramount. Gradually ease off the accelerator and avoid abrupt braking to prevent skidding.

Choose your lane wisely:

Stick to the middle lanes to minimize the risk of hydroplaning. Outer lanes are more prone to accumulating water.

Visibility matters:

Turn on your headlights and be careful of other vehicles to the rear and in blind spot areas as they are especially difficult to see through rain-spattered windows.

Watch out for slippery roads:

Be extra careful during the first half hour after rain begins. Grime and oil on the road surface mix with water to make the road slippery.

Keep a safe distance from large vehicles:

Large trucks and buses can reduce your visibility with tire spray. Avoid tailgating and pass them swiftly and safely.

Mind your windshield wipers:

• Overloaded wiper blades can hinder visibility. If rain severely limits your sight, pull over and wait for conditions to improve. Seek refuge at rest areas or protected 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.

Source: The National Weather Service