The ash would be loaded with silica in micron sized particles. Air filters don’t grab enough of it to save engines...or lungs. It would be like dumping fine sand down your intake manifold the grant will also chew up gas turbine compressors and coat the burners and turbines with molten silica. Everywhere under that ash cloud will be immobile and also getting pulmonary fibrosis. P100 filters would save your lungs but will clog so fast as to of little use other than maybe trying to flee the ashfall area, on foot because vehicle engines will be chewed up in short order. Yellowstone kills North America as a viable place to live for decades until rains wash all the ash out of the air, fields and waterways.
Not to mention the ash fall on roves will soon collapse the strongest ones.