What happened to this weekend’s snow in the Black Hills?

RAPID CITY, S.D. – Let’s take a look at at what was expected from this system, what actually happened, and why we didn’t see things play out exactly like we anticipated.

We’d love to see your photos of the first snowfall! Please submit them above.

What was expected?

The heaviest snow was expected to fall in the northern Black Hills and the Devils Tower area, as well as near the Bighorn Mountains.

3-6 inches were expected for the hardest hit areas.

Snow Total

Snowfall1023

What actually happened?

The hardest hit areas were correctly identified, but the amounts were less than anticipated. The northwestern plans were also hit a little harder than originally expected. Official snow fall totals will be reported by the NWS over the next couple of days as more information is collected. There were some unofficial reports of  2.5+” south of Lead and some 1″ accumulation in other parts of the northern Hills and northern plains.

Why did expectations differ from reality?

The first thing to point out is that the snow maps shown above are for the snow FALL, and not the snow ACCUMULATION.

The accumulation for early season events, like this one, will always be significantly less than the amount that actually falls.

Another reason for the low snowfall amounts in the southern and eastern portions of the Black Hills is what’s known as a dry pocket.

Dry pockets happen when there are downslope winds that cause the air to warm up.

Because the amount of moisture (think dewpoint temperatures) stays constant, this causes the air to become unsaturated and the precipitation will evaporate.

Snow Dry Pocket

There was also less snow than expected over most of the region. This was caused by a lack of moisture that was able to be ingested into the system. Almost every weather model was expecting a larger amount of moisture to be present, and result in higher precipitation totals.

Early season snow is always difficult to forecast, especially the exact amounts.

That’s the reason why we stressed the areas that would see the most significant impacts, rather than focusing on the amount of snow that each area would receive.

Categories: Local News, Weather Daily