ALBANY, N.Y. (AP) — Not-so-frozen lakes have claimed 10 snowmobilers across the Northeast so far in a relatively mild winter.

Seven snowmobilers have died and another three are missing after crashes through lakes that looked deceptively solid because they were blanketed with snow.

Most of the accidents happened in New York state, where officials warned that, despite recent snowfalls, many lakes have not had enough cold days to develop ice thick enough for riding. And most have involved experienced snowmobilers in their 50s and 60s who have been riding most of their lives.

That thin ice is due to a statistically mild winter. Temperatures in the Adirondacks region, for example, were 11 degrees above normal in January and 6 degrees above normal so far in February.