What's the difference between 5,000mm and 10,000mm waterproof rating in casual pants?

5,000mm waterproofing handles light snow and brief exposure to moisture—adequate for dry, cold resorts with occasional snowfall. 10,000mm provides noticeably better protection, handling moderate snowfall, wet chairlift seats, and brief contact with slush without leaking. If you ride at coastal or notoriously wet resorts (Pacific Northwest, Northeast ice coast), or if you frequently encounter wet conditions, the upgrade to 10,000mm is worth the modest price increase.