it does seem very plausible that undetected cases are several times higher than confirmed/symptomatic cases. and/or, perhaps when things start to spike locally

it does seem very plausible that undetected cases are several times higher than confirmed/symptomatic cases. and/or, perhaps when things start to spike locally people begin to take it seriously and change their behavior a bit -- distancing/masks were not very common in the Dakotas before the post-Sturgis wave.