So, the good news: CASHMERE + RAIN = HARMLESS!! (Unless it's acid rain or something) If you don't let it hang on a hanger (one of the cardinal rules about cashmere!!) then you should make it out OK. Apparently, cashmere is not damaged by rain like the vachetta on your Louis Vuitton. Leave that inside.
Right after I hung it outside. Look at the shoulders.
The next morning. Here you can see how the weight of the water has pulled at the shoulders.
And even more.
I hope this helps those of you who live in rainy climates!