A senior council official said it shows how "one outbreak can create significant turbulence and concern" after the town registered the highest rate of new cases in England.
Officials from North Yorkshire County Council said on Wednesday they believed the intensive testing ongoing at the site would push Selby's case rate even higher before it begins to subside.
Richard Webb, North Yorkshire's director of health and adult services, reminded a virtual press conference how he described the situation in the county last week as "encouraging but volatile".
Mr Webb said on Wednesday: "I stand by that assessment even though the last seven days has put a greater emphasis on the volatility."
He said Selby's current seven-day case rate was 109.2 cases per 100,000 people - up from 46 a week ago.
This is much higher than the rate of 70.5 in the next local authority on the list, which is Kirklees in West Yorkshire.
The warehouse believed to be at the centre of the outbreak, Clipper Logistics, has said there "is no evidence to suggest these cases were contracted in the warehouse".
When asked about this at the North Yorkshire Local Resilience Forum Mr Webb said: "At this stage, it's always premature to come to a conclusive view about the cause of any particular outbreak or spread.
"We are looking at all options. You cannot rule anything out at this stage."
PCR testing at the warehouse is ongoing, as well as contact tracing.
Public health consultant Victoria Turner told the meeting that Clipper's measures "have generally been good" but officials were giving further advice.
She said testing was picking up asymptomatic cases, adding: "Whilst this does give us a higher peak in cases in the short term, it should break these unseen chains of transmission that could otherwise prolong any outbreak."
Clipper Logistics said in a statement: "As this global crisis progresses, it's clear no community is insusceptible to coronavirus and, like many others, we, too, have been impacted with a number of confirmed cases.
"That said, there is no evidence to suggest these cases were contracted in the warehouse."