Accidents and illness can happen anywhere, even in paradise. That's why it's important to know how to prevent them.

Mask skills? Haven't practiced them since open-water class? Know this--one day your world is gonna get very blurry.

Remember, you need your mask to see clearly, but you don't need it to breathe and you still have vision (albeit blurry) without a mask or with a flooded mask. If you haven't practiced swimming 20 to 25 yards without your mask in a pool or shallow water, then you probably aren't prepared for a major flood or loss of your mask. Many police officers have never fired their side arm in self-defense. But they still must regularly qualify on the pistol range. Never take emergency skills for granted.

Step 2: Find it

After calming your breathing and ensuring you're still neutrally buoyant, determine if the mask is still present and functional. It probably will be. The most common causes of full floods are a current twisting the mask on your face, someone's fin dislodging it, bumping it against something to break the seal, the strap coming loose or breaking, or the strap buckle failing.

In most instances, you will be able to reposition the mask on your face and clear it using the appropriate technique for your mask type (purge valve/non-purge valve; high volume/low volume). If a part is broken and you must hold the mask in place to maintain a watertight seal, signal to your buddy and abort the dive according to your agreed-upon plan. Don't forget to make a safety stop, if practical.

Step 4: Get guidance

If your mask has become non-functional due to cracking of the faceplate, a torn skirt or unplanned trip into the inky depths, signal your buddy for assistance to make a controlled ascent. Again, if practical, include a safety stop.

Step 5: Use your spare mask

Unless you have one, your diving day is probably over. You do carry a save-a-dive kit, don't you?

Pro Tips

• If you buy your mask at a professional retail store, you should have a hard case. Keep it and use it, in your travel kit and your onboard gear bag.
• When you and a buddy are practicing your mask skills during your next training dive, try this old pro trick: Give your mask to your buddy. Cup your hands below your eyebrows and around your eyes. Now, exhale bubbles into your cupped hands and look down. When done properly, you can displace enough water to create an air space to allow your eyes to focus.
• Oh, that black stuff that gets on your mask's silicone skirt? It's called "mold," or "the fungus among us." Try some Soft Scrub or toothpaste to clean up your act, and make sure your mask is completely dry next time before storing it—in its hard case, of course.