Well, this is certainly an unusual word, and one that I had never heard, so a rousing thank you to the individual who precipitated my return with this request.
Lauwine, accordingly to OED, apparently derives from the German "lau" for mild or tepid, from the actual German word lawine, which quite simply, means an avalanche. But lawine derives more realistically from the Latin "labina" for "sliding, chutes" from "labi" for "to slide". The derivative spelling was only in favor in English in the 1800s with its advent in Byron's poem, Childe Harold's Pilgrimage, and shares the same "lau" with the Sweizerdeutsch ("laui", "lauene", and "lauine"), which is more likely the source of the extra "u", rather than some forced meaning with "tepid".
As for use of the word, I think your audience would be more perplexed and put off by a literal use of lauwine ("let's see if this dynamite will trigger a lauwine"), and as a warning, it would be just about useless (Run! the lauwine is coming!) Now, for connotive usage, I love the word "flood", but I could give "lauwine" a try for some variety, after all, it is just another state of water. Instead of a flood of applications for the prestigious internship, one could reference a lauwine of applications. From context, the listener should get it, although I would still imagine with a perplexed look. Are you trying to sound pretentious? Probably. Why not. It's lauwine! What else are you going to do with this word besides relegate it to the archives? Good luck, and don't let all those old words cover you in a lauwine.