Driven by sudden jumps in death counts in Alameda and Santa Clara counties, the Bay Area's pandemic death toll just took a depressingly big leap on Friday, with 42 new fatalities.

It may be that not all of these deaths occurred in a single 24-hour period, but technicalities aside, the Bay Area has not seen a day with this many new deaths to record since the pandemic began in March. The count is likely being driven by the July and August spike in virus cases and hospitalizations, with deaths from the coronavirus often occurring four to six weeks after hospitalizations begin. Following the July spike, 312 Bay Area residents died from COVID-19 during the month of August, marking the deadliest month so far.

Santa Clara County has been inconsistent in its daily reporting this week, and no new cases or deaths were posted to the county's website on Thursday. But as of Friday afternoon, the county's public health department had added 289 new cases for a cumulative total of 19,143 — a 1.5-percent jump. The website also indicated that only 8 of the deaths in its total of 276 were new, however that marked a 13-person jump from the previously reported total of 263 two days earlier.

Alameda County also marked another week with a grimly large death toll, adding 17 new deaths on Friday alone.

Sonoma County also had one of its biggest days for mortality count from the virus, adding seven to the regional total. With five other deaths added from San Francisco, San Mateo, and Contra Costa counties, the day's total reached 42, and the cumulative total from the pandemic stands at 1,278.

This latest tally arrives a week after Alameda County and the Bay Area marked especially high death tolls. The highest one-day death toll previously for the region had been August 25, when 28 people died from the virus.

Still, the overall trends in the region and the state have been positive in the last several weeks, and more counties are reaching new "tiers" under state guidelines for reopening. This week, both Santa Cruz and Santa Clara county joined San Francisco and Napa in the "red" tier, allowing for more businesses to open. And on Thursday, San Francisco announced a loosening of restrictions for indoor gyms, and indoor services at hair, nail, and waxing salons, effective Monday.

The spike in cases in July, which we now may be seeing the tragic final results of here in the Bay Area, remains a stark reminder of how quickly things can go south with this pandemic. Vigilance, mask-wearing, and staying at home more than you'd prefer all remain keys to keeping the virus under control, and preventing more preventable deaths.

As Dr. Anthony Fauci said in comments this week, we should all be prepared to "hunker down" this fall and winter as cases likely resurge in some places. And in reaction to comments from the president about the country "rounding a corner" with virus cases, Fauci shot back in an interview on MSNBC on Friday saying, "I’m sorry, but I have to disagree with that because if you look at the thing that you just mentioned, the statistics, Andrea, they’re disturbing. We’re plateauing at around 40,000 cases a day and the deaths are around 1,000."

He added, "When you have a baseline of infections that are 40,000 per day and you have threats of increased test positivity in certain regions of the country, such as the Dakotas and Montana and places like that... You don’t want to start off already with a baseline that’s so high."

Related: Bay Area Coronavirus Information — Updated Daily