Emergency Flares: Are they Waterproof?

Chemical roadside emergency flares are an invaluable addition to any flat tire kit or vehicle carried survival kit. Almost nothing is as bright and noticeable as the flickering, red flame of a roadside flare.

Designed to be used whenever a roadside emergency occurs, this naturally begs the question of whether or not these flares are waterproof, seeing as they may have to be used in all weather conditions. Will these chemical flares stand up to immersion in water?

man using an emergency flare

Yes, most roadside chemical flares are water resistant, but not waterproof, and work if exposed to incidental contact with water, such as that of rainfall. However, continued exposure to immersion in water will likely degrade or destroy these flares.

Nobody wants to pull out their roadside flares only to discover they are useless because they got a little damp one time. There is much more to learn on the subject, and we will delve into it below.

Most Roadside Flares are Water Resistant, Not Waterproof.

Chances are, unless you are careless with your flares or deliberately use them in a wet setting, you don’t have much to worry about.

Chemical flares, even though they function very much like a giant match, are designed to put up with exposure to moisture and still function reliably, particularly if they are lit prior to being exposed to moisture.

As you might expect, roadside emergency flares must be used day or night in all weather conditions and that includes rainfall, sometimes heavy rainfall, and if they wouldn’t work in those settings then they wouldn’t be worth carrying.

Typically constructed with a heavy, wax or silicone coating applied around a paper sealed tube, the design of the flare is intended to preclude water from leaching into the casing and reaching the chemicals within.

This is obviously not a guarantee, and like all such combustibles are notorious for going bad or degrading when exposed to moisture, typically contact that is unknown by the user, and then being placed back into storage.

Exposure to Water Will Often Degrade or Destroy Flares

This exposure to moisture will degrade the flare in any number of ways, including adverse reactions with the chemicals that produce the flame when lit or even damage or destruction to metallic parts or the striking mechanism if installed.

Water is thought to be the ultimate solvent and that is definitely true when it comes to your flares.

In short, anything but the most incidental contact that is quickly remedied should be cause for disposing of your flares and replacing them with new ones, unless you want to roll the dice and take your chances with a flare that won’t work or, even worse, potentially malfunction in a dangerous way.

It should go without saying that any roadside flare that has been submerged or inundated with water prior to its activation should be considered non-functional and disposed of appropriately in accordance with all local and national laws for combustibles or hazardous materials.

Maritime and Submersible Flares Offer the Ultimate in Waterproofing

For those of us who live in the rainiest places or are worried about moisture exposure damaging or degrading our flares, there is hope and we do have several solutions for the problem.

A cousin to common chemical flares carried in automobiles is a variety that functions very much the same but is designed for maritime use, typically carried for signaling purposes aboard boats and other ocean going vessels.

These maritime flares are designed to be the first and last word in waterproofing, and only sustained immersion will degrade or destroy them.

They can be splashed, dunked and otherwise soaked and so long as this does not happen over an extended period of time the flare should be expected to function normally, and they can even be lit and then thrown onto the surface of the water.

If you can believe it, there is an even more specialized version of chemical flares that are designed to be used underwater. That’s right; these flares are fully submersible and capable of being lit underwater! That is truly remarkable.

As you are probably expecting, both maritime and submersible flares are generally not as easy to come by for most of us as standard roadside flares and they can be significantly more expensive, but for the ultimate assurance of reliability in wet environments they are a good option.

Keep in mind, depending on your state and local laws flares of this type might not be legal for use in a roadside setting. Check with your Department of Transportation to be sure.

Some Flare Alternatives are Waterproof, Too

Some folks, for whatever reason, don’t like chemical flares as roadside sign signaling devices. Maybe they have concerns about reliability or reusability, or maybe they’re just worried about the fire risk that is inseparable from the operation of such flares. In that case, we still have solutions for you that work well enough for the purpose.

One increasingly popular option is a battery powered flare, or strobe. Although there is always a risk of shorting out one of these devices should water infiltrate its casing, in particular the battery compartment, most are designed with ruggedness and operability in mind in any environment, including hard rain.

Be they battery powered or rechargeable, if you get a good brand you should expect it to work flawlessly even in a wet environment, though not, probably, if completely submerged.

Another option is the common chemlight, or glow stick.

Consisting of a binary chemical solution that luminescence when combined in a sealed casing, this chemical reaction takes place in a ruggedized housing that is completely sealed against the environment and that means there is little if any chance that water could infiltrate the casing to dilute the chemicals or otherwise disrupt the reaction.

Though they are not as bright or noticeable as chemical flares, they are still quite usable and can be had in a variety of colors including red and orange.

Chemlights also have an advantage and that they are completely, utterly safe, or about as safe as any signaling device can be. They are non-toxic, generate no heat, and can be used pretty much anywhere and everywhere with no regard for accidents.

Combined with their inherently waterproof nature, these might be just the ticket for some of you.


Chemical roadside emergency flares are typically water resistant to allow their use in rain or after exposure to incidental water immediately prior to deployment.

They are not, as a rule, waterproof and any prolonged exposure to water to say nothing of full immersion is highly likely to damage or destroy the flares and it may lead to erratic operation if they function at all.

If completely waterproof flares are desired those designed for maritime or submersible use should be sought out as they offer a degree of water resistance far beyond those sold for use on the roadways.

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