As coronavirus cases surge in a number of places in Japan, most notably Hokkaido in the far north and Tokyo, the government’s task force on the pandemic has warned that more needs to be done to head off a deeper crisis in the coming winter months.

Tokyo officials reported 293 new Covid-19 cases on Tuesday, up from 157 on Monday and 189 the previous day, bringing the total number of infections in the capital to more than 32,000. As many health experts predicted, cases appear to be trending upwards with the arrival of the colder weather, with 4,921 cases in September and 5,328 in October.

In total, over 108,000 cases have been reported nationwide and the statistics hint at a growing “third wave” of infections during winter.

Hokkaido appears to be leading that trend, with at least 160 cases on Tuesday and a record 200 new cases on Monday, surpassing the previous high of 187 new cases on Saturday. Across Japan’s largest prefecture, 4,198 people are being treated and experts warn that hospitals are already coming close to capacity.

“This is a really serious problem for Hokkaido as temperatures and humidity levels are dropping, meaning that people are keeping their windows closed to keep the warmth in and we know that it is easier for the virus to spread in a closed environment,” said Yoko Tsukamoto, a professor of infection control at the Health Sciences University of Hokkaido.

“Ideally, we need people to keep their windows open or at least ventilate shared spaces as much as possible, but that is not always possible because temperatures are falling now,” she said.

“Experts have been predicting that the problem was going to get worse in the winter months so this is not a surprise – but I do not think they knew that cases were going to increase this rapidly again,” she said.

“It’s faster than we expected, the experts are worried and if it can happen here in Hokkaido then it will definitely happen in Tokyo and elsewhere in Japan when temperatures fall there.”

The government’s panel of experts has expressed similar concerns, cautioning that case numbers will rapidly increase unless emergency countermeasures are introduced immediately.

The panel is proposing efforts to avoid clusters of cases emerging and then spreading to the wider population, as has been seen in several cities. Clusters have largely been traced back to the nightlife districts of major cities, such as Tokyo’s Kabukicho district and the Susukino area of Sapporo, the biggest city in Hokkaido.

Many of those cases were linked to host or hostess bars that did not fully implement social distancing recommendations.

Clusters have also been reported at schools and universities, where younger people may not display symptoms but can spread the virus.