Dr. Angela Dunn, Utah's epidemiologist, made the dire warning in a memo obtained by ABC Salt Lake affiliate KTVX on Monday.
"All of our goals are aligned - keep the economy open and prevent deaths/ illnesses. We are quickly getting to a point where the only viable option to manage spread and deaths will be a complete shutdown. This might be our last chance for course correction. Contact tracing and testing alone will not control this outbreak," Dunn wrote.
Dunn encouraged the state to put a pause on any more loosening of restrictions until July 1 and mandate that face coverings be worn.
"This might be our last chance for course correction," Dunn wrote.
Despite Dunn's memo, Gov. Gary Herbert said in a statement he has "no plans to shut down Utah's economy."
"Dr. Dunn's internal memo raises alarm about the increasing COVID-19 cases in Utah. I appreciate her analysis and share many of her concerns. We will work to stem this tide, but I have no plans to shut down Utah's economy," he wrote on Twitter.
Herbert urged Utahns to protect themselves "by following our common sense guidelines for social distancing, good hand hygiene and especially the use of face coverings."
Utah is one of a handful states that have seen an increase in hospitalizations, deaths and rate of positivity, according to an ABC News analysis of state-released data compiled by the COVID Tracking Project. The rate of positivity measures how many tests are positive for COVID-19 compared to the amount of tests run.
The state entered the yellow phase of its COVID-19 response on May 15 and the surge in new cases began about 12 days later, according to KTVX.
The following day, the state reported the largest single-day number of new virus cases for the third consecutive day.
There are 17,906 COVID-19 cases in the state so far, according to the Utah Department of Health.
ABC News' Arielle Mitropoulos, Brian Hartman and Soo Rin Kim contributed to this report.