Definition
A NOTAM contraction used to report that a runway surface is covered by wet snow — snow that contains enough liquid water to stick together and pack down, but is not slush or standing water. Wet snow significantly reduces braking action and directional control during takeoff and landing.
Plain English
A short code in airport notices meaning the runway has wet, sticky snow on it — the kind that packs into a snowball rather than blowing around as powder.
Context Anchor
Seen in NOTAMs and airport surface condition reports before departure, approach, or landing.
Why Pilots Care
Wet snow reduces braking effectiveness and increases the chance of skidding on takeoff or landing.
Grounding Statement
Picture partly melted snow lying on pavement: it is not just water, and it is not dry snow, so aircraft tires may not grip normally.
Intuition Check
Do not read WSR here as weather radar or snow somewhere near the airport. In this NOTAM context, WSR means wet snow is on the runway surface itself.
Example Sentence 1
The NOTAM listed WSR for runway 27, so the crew added contaminated runway corrections to their landing distance calculation.
Example Sentence 2
Airport ground crews posted WSR to alert inbound flights of the slippery surface.