Cloud seeding for ski resorts

Glaciogenic seeding targets clouds that already contain supercooled liquid water and are precipitating inefficiently. It converts some of that liquid to ice so it can fall as snow instead of passing over the range. It does not create storms, and it does nothing in a dry winter with no suitable systems. The realistic framing for a resort is a possible improvement in seasonal natural snowfall across many storms, not a guaranteed result in any given week.

• Orographic lift. Storms forced over the terrain generate supercooled water continuously through an event — the condition seeding depends on.
• Defined target. A resort's terrain and the basin above it are a small, well-mapped area rather than an abstract region.
• Consistent storm tracks. Many western ranges see repeated flow patterns, which makes targeting and evaluation more tractable.

• Snowmaking offset. Natural snow displaces pumping hours, water withdrawals, and electricity — a measurable operating cost.
• Early and late season. Shoulder periods are where a marginal storm most affects open terrain and revenue.
• Terrain snowmaking cannot reach. Off-piste, bowls, and upper-mountain terrain depend entirely on natural accumulation.
• Watershed alignment. Snow that falls on resort terrain also feeds the same basins municipal and agricultural users depend on, which often makes a resort program easier to coordinate regionally.

Resort terrain is difficult for both traditional delivery methods. Ground generators depend on uncertain vertical transport over complex topography; crewed aircraft face icing and terrain risk in exactly the night-time winter storms that matter most. Uncrewed aircraft can place material in the cloud over the intended terrain without putting a crew in those conditions, and each flight returns position and atmospheric data. See drone cloud seeding and the comparison of delivery methods.

• Which storms will you decline to fly, and on what criteria?
• How is the target area defined relative to our terrain, and how is trajectory handled?
• What permits, registrations, and airspace authorizations apply, and are they in place?
• What suspension criteria apply for avalanche or flood conditions?
• What records do we receive per mission, and per season? See mission reporting.
• How will the program be evaluated, and over what time frame?

Be cautious with any operator who answers the effectiveness question with a single confident number. Honest answers cite the published literature, describe uncertainty, and commit to multi-season evaluation. More on that in our FAQ.