As Minnesotans observed Memorial Day, the official start of summer, the number of COVID-19 patients needing intensive care beds climbed to a record high of 248, increasing by the largest number in a single day.

State Health Department officials who released the numbers Monday said they confirm earlier warnings that the numbers would inch up.

"This is an expected trend," said Jennifer DeCubellis, CEO of Hennepin Healthcare, which oversees HCMC (formerly Hennepin County Medical Center). "We anticipated that social distancing would allow health systems time to get space, staff and supplies in place in order to be better prepared for higher volumes — but that the volumes would still increase, ideally at a slower and more manageable pace."

The Health Department also announced 12 additional deaths, bringing the number of Minnesota fatalities caused by the virus to 881.

The 248 ICU beds in use surpassed the previous daily high reported Friday, when 233 were in use. That number had dropped to 207 by Sunday.

The 41-patient spike in ICU beds in use from Sunday to Monday was the largest single-day increase since the pandemic arrived in Minnesota in March.

The previous single-day increase was reported May 16, when intensive care beds in use jumped by 25 to 225.

To prepare for the increased need for critical care beds ahead of the three-day holiday weekend, HCMC opened an ICU surge area last Wednesday, DeCubellis said.

"Our biggest pressure point is on the staff who are managing high acuity care, in higher volumes, and with longer lengths of stay," she said, adding that they are "truly focused on the mission of caring for our community under all circumstances."

Department of Health spokesman Scott Smith said that even with the increase in the use of ICU beds for COVID-19, there is enough capacity to care for patients.

In the Twin Cities metro area, 87% of ICU beds were full Monday. During the influenza season, it's not unusual to have ICU beds filled to more than 95% capacity, Smith said.

Other regions of the state have lower percentages of occupied ICU beds, he said.

In addition to the high number of COVID-19 patients, HCMC is the state's largest Level 1 trauma hospital, so staff and resources must be available for acute trauma care. HCMC has the state's only emergency hyperbaric chamber and is one of only two critical-care burn centers.

The Health Department also reported 357 COVID-19 patients in hospital beds Monday that aren't in intensive care units — the highest number to date. The previous high was 353 on Saturday.

Overall, the Health Department announced 745 newly confirmed cases of COVID-19 on Monday, bringing confirmed cases in the state to 21,315. That number is estimated to be only a fraction of those actually infected.

Of the newest announced deaths, 10 were in long-term care, assisted living or group behavioral-health facilities, and all victims were between the ages of 60 and 99, according to the Health Department.

About two-thirds of people in Minnesota confirmed to have COVID-19 — a total of 14,816 — have recovered from their illness and no longer need to remain in isolation because they haven't had symptoms in 14 days.