If the UK mutated new version of Coronavirus is 70% more contagious and much more likely to be fatal:

 it then makes perfect sense why people are worried that up to 731,000 could be dead by April 1st here in the U.S.

However, if they are not considering the differences with the new UK mutated virus the death rates might be even worse than this. (If these projections are based upon the less contagious and less lethal version of the virus that mostly has been around since the Spring here in the U.S.)