Small-craft advisories and when to stay ashore

What it means

A Small Craft Advisory (in some regions "Small Craft Warning") is issued by the National Weather Service when sustained winds or seas are expected to hazard smaller vessels — typically sustained winds around 18–33 knots and/or seas that small craft handle poorly. On inland lakes, the wind criterion dominates: forecast sustained winds in the low 20s will usually trigger one.

"Small craft" has no legal definition. It targets boats — and crews — that are vulnerable to capsizing, swamping, or being overpowered. A daysailing dinghy, a kayak, a small fishing boat: small craft. A 40-foot keelboat with a deep keel and a professional crew: less so, though even they respect steep lake chop.

Translating it to your lake

Advisories are regional; your lake is local. The deciding factors are fetch and exposure. Twenty knots on a two-mile pond builds short, steep, annoying waves. Twenty knots down the eight-mile axis of a big reservoir builds genuinely dangerous chop for open dinghies, with breaking whitecaps and no rescue shortcuts. Check the advisory, then check what that wind direction does over your lake's longest fetch.

Our sailing score folds this in approximately — hours above 22 knots score poorly in every profile — but a score is not a substitute for an official advisory. Links from every lake page go to the NWS forecast for the lake's zone; when an advisory flies, the score should already be red. If it is not, trust the advisory.

The honest go/no-go checklist

Go if: winds are inside your profile band, gust factor is below ~1.5, no precip probability above 45%, water temp is survivable for your gear, and your boat is rigged for the gusts, not the average. Stay ashore if any of those flip — especially the gear one. The most common serious incident on small lakes is not a surprise storm; it is a warm sunny 20-knot gust-fest that a capable sailor in the wrong boat went out to "just have a look at."