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Weather Stations

Weather Models (forecast length, forecast frequency)

▫️UW High Resolution Precip Model (72 hours, runs every 12 hours)

▫️HRRR Model (Pivotal)  (24 hours, every hour)

▫️ECMWF (Pivotal) (144 hours, every 12 hours)

Stream Flow Gauges

▫️Icicle River Flow

▫️Wenatchee River Flow

Notes:

1️⃣  After a rain event (.1” or greater), the icicle canyon is generally climbable when the relative humidity of the ‘Icicle House, WX’ station drops below 65%.

2️⃣ Temperature inversions overnight are pretty common in Leavenworth in mid->late spring and early->mid fall, when it may be 5-10 degrees colder in the icicle valley and the lowest parts of the canyon than at higher elevations.

3️⃣ The rock's coldest surface temperature is usually 30-60 minutes after daybreak, as the day's minimum temperature is generally around that time, and the cold air continues to influence the rock's temperature until the air temperature begins to rise.

4️⃣ Moisture/dew is not generally a problem on the surface of the rocks, as the stones remain above the dewpoint temperature as the overnight temperature declines to the minimum just after daybreak.

▫️Moisture dew is much more common when a warm front follows a cold period, when the rock is colder   than the dewpoint temperature, and can cause condensation/dew.

5️⃣ Leavenworth is VERY climbable in the winter time during a high pressure window if your willing to shovel off boulders, a week of sunny weather and a shovel can go a long way.

Theories:

(no I cant prove these, but I do have some data)

Forest Fires and Rock Brittleness

Leavenworth’s rock can be very brittle and there are various theories for this, but I think the leading theory from my perspective is that granite begins to see deformations in its structure at aronud 800 degrees fahrenheit, which is about the same temperature as low end forest fire burns. The granite around leavenworth is around 100 million years old and has been exposed to likely thousand’s of fires making it break and fracture in a featured way that is great for climbing, but also brittle. I do not think that water or cold weather has any effect on increasing brittleness and if something is breaking already its likely only a matter of time.

Unfortunately leavenworth’s rocks will continue to break, but on the upside it will continue to leave new variations of old classics’s for the future generation’s and in a thousand years problems that dont currently exist may be climbable as fires and weathering create new holds.

Climate change and more good weather windows

As climate change continues Leavennworth will become a winter bouldering destination. Leavenworth generally has its best conditions in both Late-Fall/Early-Winter or late-winter when it is still very cold. As climate change continues I would expect to see outlier years where there little to no snowfall in the canyons leaving many boulders accessible throughout the winter and providing ideal climbing conditions during dry weather spells.

Flow Levels For River Boulders: