The doubling period of Covid-19 is between 1.8 and 4.1 days where large scale quarantine measures aren't being taken [1][2]. The conference is in 43 days so without large scale quarantines and stopping large events then the number of cases in the US could grow to as many as 800,000 assuming a doubling period of 3 days. It seems therefore fairly obvious that most large events in April will have to be cancelled.
Its difficult to tell because the US hasn't been doing as much testing as other countries. You can look at the curves for various countries at https://covid.bio/ Most countries that haven't initiated large scale quarantines have a doubling period of between 1.5 and 5 days
I think the numbers can't be looked at that way for a variety of reasons, primarily the fact that we are rapidly expanding testing capability in the US right now, so we will see a rapid increase in the number of diagnosed cases. However that does not mean there is the same rapid increase in the number of cases so quickly. Basically we are going to be catching up with cases from the past 2-4 weeks in the coming week.
No there are other estimates of a few hundred cases in the bay area that are sensible. Or at least they were a week ago. To get two in-the-wild cases serious enough for hospitalization and testing (overriding the CDC testing criteria at the time) you'd expect there to be at least around 100-200 cases at the time of hospitalization.
[1] https://link.springer.com/article/10.1007%2Fs15010-020-01401... [2] https://onlinelibrary.wiley.com/doi/abs/10.1002/jmv.25723