Fires last summer left slopes above the road susceptible to mudslides.
There have been several already which have closed I-70 for at least a day or two.
CDOT's plan for the summer is to close that stretch of I-70 whenever the weather service forecasts a flash flood warning for the area.
The idea is to preclude having folks get washed away or trapped by slides if they occur.

Which means that I-70 might be a less reliable E-W route than you'd expect. For this summer anyway....