I just went to the NOAA site for Rapid City to check their forecast discussions, which you can find on most NOAA websites.
The first time they looked at their models and issued the blizzard warning was 3:22 pm, Thursday October 3rd. By that late in the day, there was precious little any rancher could do. The next day, the blizzard set in.
That’s how little time they had: About 12 hours from the prediction to the start of the heavy snowfall.
Here’s the link to the discussion:
Now, fast-forward through several updates to about 12 hours later, and you see how NOAA changed their tune - big time:
Again, there was no “several days’ notice.” There was at most, one day - and more like 12 hours.