COVID-19 cases are surging in rural places across the Mountain States and Midwest, and when it hits health care workers, ready reinforcements aren’t easy to find. In Montana, pandemic-induced staffing shortages have shuttered a clinic in the state’s capital, led a northwestern regional hospital to ask employees exposed to COVID-19 to continue to work and emptied a health department 400 miles to the east. … In North Dakota, where cases per resident are growing faster than any other state, hospitals may once again curtail elective surgeries and possibly seek government aid to hire more nurses if the situation gets worse, North Dakota Hospital Association President Tim Blasl said.