Government shutdown impact

My family and I are planning a spring break trip to some national parks. Unfortunately our spring break starts March 14th. Should we anticipate that the parks will be closed starting on Friday the 15th (due to a lapse in annual government appropriations) and that we won’t be able to obtain back country camping permits? Or would a park closure start on Monday the 17th if the government shuts down? Just trying to come up with a back up plan….it sucks that this is even a distinct possibility.