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What is a Small Craft Advisory? Why is It Important?

Written by J. Harvey / Fact checked by S. Numbers

what is a small craft advisory

Let me guess, you’re here because you encountered the term “Small Craft Advisory” in your local news outlet or on social media sites like Facebook and Twitter, and thought, “What is a Small Craft Advisory?” Why the emphasis on “small craft”?

It’s a warning issued by the National Weather Service if water and weather conditions become unfavorable for tinier watercraft.

Wind speed from 18 knots to 33 knots and wave height of at least 5 feet are often enough to warrant the issuance of small craft warnings.

What Does a Small Craft Advisory Mean and Why is It Important?


Well, you can’t get any more straightforward with the Small Craft Advisory meaning based on its name alone. They’re meant solely for small boats since they’re more prone to the dangers posed by inclement weather and water conditions.

1. What is considered a small craft?


Those spanning less than 65 feet. So if you’re wondering what size boat this warning applies to, then anything below that should comply. 

As for what determines when they’ll be issued, it’s often determined by wind speed and wave height. Once they become unfriendly to small crafts, the Small Craft Advisory will be issued to indicate a low degree of danger.

Still, boaters should heed it, since small-vessel operators are essentially putting themselves at a heightened risk if they still decide to head out. Being able to help these watercraft to avoid their common problem (i.e. their accident proneness) is what makes a Small Craft Advisory invaluable for boaters at large.

In the US, it’s actually the first in a hierarchy of warnings. A Gale Warning will be issued once the winds become a stronger 34 to 47 knots, for example, and it can be further bumped into a Hurricane Warning once they reach 64 knots and above.

2. Example of small craft advisory


An example of a message issued by the National Weather Service would be:

“For the Small Craft Advisory, west winds 25 to 30 kt with gusts up to 35 kt, and seas 6 to 11 ft expected.”

It’s often issued alongside other warnings like gale and storm warnings. Boaters need the necessary information as soon as possible, so it only reveals the most pertinent one ASAP.

These messages are regularly updated and can be read on the said government agency’s main website,, or other ways like marine weather statements, local media, social media, etc.

Keep in mind that what wind speed or wave height each state or even the regions within it would deem as  Small Craft Advisory-worthy is entirely up to them. For example, the threshold could be slightly higher in Northern California than the rest of the state – much more or less so in other states.

You’ll see the patterns and thresholds better if you’ll observe local advisories.

Other Factors That Affect Small Craft Advisory

Besides boat size, wind speed, and wave height, these are the other elements that may contribute to the issuance of this advisory by the National Weather Service.

1. Weather patterns


May they be thunderstorms or hurricanes, a Small Craft Advisory may also be issued for weather disturbances in the area. These often cause heavy rains and strong winds that make water conditions inordinately dangerous. 

2. Boat type


We can’t ignore that some types of boats are better designed to handle rough conditions. Trawlers and sailboats deserve a special mention since they integrate displacement hulls that substantially boost stability – enough to curb the challenges of a vicious sea.

3. Experience of the operator


Beginner and experienced boat operators alike need to take note of this advisory once issued.

However, it can be argued that more adept boaters can make a case for still going ahead with a trip despite the warning. Why? They’re more able and equipped to handle these hazardous conditions.

Remember, it’s an advisory – not a total restriction.

Warning Flags and Light Signals Are Also Often Used


Flags and light signals are more convenient weather warning for boaters since they’ll be able to immediately inform them of the presence of danger and how risky it is without relying on words. There’s a flag assigned to Small Craft Advisory, Gale Warnings, Hurricane Warnings, etc.

What flag is used to indicate a Small Craft Advisory? The Small Craft Advisory flag is a single red triangle. As for its light signal, it’s represented by a red light above a white one.

This flag essentially defines Small Craft Advisory as well since it has a ready meaning.

Here are the other symbols and respective meanings for other weather warnings for boaters:

  • Gale Warning – Two rectangular flags and one white light above a red one.
  • Storm Warning – A red rectangular flag with a black rectangle positioned in the middle and two red lights.
  • Hurricane Warning – Two red rectangular flags with a black rectangle with a pattern of two red lights above and below a white one.


I hope I’ve cleared up any doubt you may have regarding the Small Craft Advisory definition and how boat size, type, and operator experience figure into it. The wind speed and wave height thresholds should be obvious since they’re regularly revealed in the National Weather Service’s stream of advisories.

Knowing the answer to “What is a Small Craft Advisory?” takes remembering the flag that represents it and wisely deciding whether your current boating skills will require you to forgo your trip altogether or not.

Read more: Smoker’s craft boat factory location.

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