The US death rate is approximately 900 per 100,000 people. Thus, for a medium sized city of a million there are on average 25 deaths per day. Not all of these deaths will be preceded by hospital care of course but that gives an idea for the scale of the case load of the health care system. The doubling time for the number of cases of Covid-19 is about 5 days. At this moment, the US has over 25 thousand cases with 193 cases in Maryland, where I live, and over 11 thousand in New York. If the growth rate is unabated then in 5 days there will be almost 400 cases in Maryland and over 50 thousand in the US. The case-fatality rate for Covid-19 is still not fully known but let's suppose it is 1% and let's say 5% of those infected need hospital care. This means that 5 days from now there will be an extra 20 patients in Maryland and 2500 patients in the US. New York will be have an extra thousand patients. Many of these patients will need ventilators and most hospitals only have a few. It is easy to see that it will not take too long until every ventilator in the state and US will be in use. Also, with the shortage of protective gear, some of the hospital staff will contract the virus and add to the problem. As conditions in hospitals deteriorate, the virus will spread to non-covid-19 patients. This is where northern Italy is now and the US is about 10 days behind them. This is the scenario that has been presented to the policy makers and they have chosen to take what may seem like extreme social distancing measures now. We may not be able to stop this virus but if we can slow the doubling time, which is related to how many people are infected by a person with the virus, then we can give the health care system a chance to catch up.