(CNN) Rescue workers are using heavy equipment to dig through the debris from a landslide that buried houses and people in the small town of Atsuma on Japan's northern island prefecture of Hokkaido.

The landslide was triggered by a magnitude 6.7 earthquake that shook the island Thursday , killing at least 20 people, collapsing houses and cutting power to millions of homes.

It's the latest in a series of disasters that have hit the country, after multiple deaths caused by a severe typhoon , flooding, and heatwaves this summer. Experts say this could be the "new normal."

As many as 40,000 rescue workers, including 22,000 troops from Japan's Self Defense Forces, worked through the night in Atsuma Thursday to search for residents feared buried in the rubble.

Families of those missing stood around anxiously as the teams dug deep into the displaced earth.

One resident, Tenma Takimoto, 17, was waiting for his sister to be discovered -- she was finally found by rescue worker who had to dig with their bare hands. Takimoto, who also suffered a leg injury, told her, "You did great. You were patient enough."

Kenichi Endo, 70, had traveled to the small town to find his relative, Japanese news agency Jiji reported. "I never expected there would be a landslide by an earthquake," he said.

The first floor of missing man's two-story house, which he shared with his wife, was submerged in mud, the report said. Endo said he loved his relative, who is in his 80s, "like a brother."

Power that was cut to millions of houses started to return on Friday, and the nearby Shin Chitose Airport, closed due to the quake, had resumed partial operation.

All domestic flights, as well as a number of international flights, are expected to be back on schedule Saturday.

Buildings lie in ruins after being hit by a landslide caused by an earthquake, on September 7, 2018 in Atsuma.

'Back-to-back-to-back events'

Japan's summer of chaos has seen the country endure weeks of deadly floods, typhoons, earthquakes, landslides and heatwaves, in what disaster management experts say is a sign of what's to come.

Thursday's earthquake came just days after the strongest typhoon to hit Japan's mainland in 25 years smashed a tanker into a bridge, forcing one of the country's largest airports to close and hundreds of flights to be canceled. The storm caused at least 10 deaths.

A ship collided with a breakwater due to strong winds whipped by Typhoon Jebi in Nishinomiya city, Hyogo prefecture, September 5, 2018.

It's one of a succession of deadly natural disasters to have affected Japan since July. "Back-to-back-to-back events seem to have beaten a path for each other to follow," Senior Science Adviser Doug Bausch of the Pacific Disaster Center (PDC) told CNN from Hawaii.

Two months ago, landslides and flooding caused by torrential rain across Japan -- from Saga in the far southwest to Gifu in the center of the main island of Honshu -- killed 200 people in what became one of the deadliest natural disasters to hit the country since the earthquake and tsunami of 2011.

A car sits in water after the area was devastated by flooding and landslides in Mabi, Okayama prefecture on July 10, 2018.

The heavy rain that led to flash flooding was based on a longer-term pattern, said Munehiko Yamaguchi, from Japan Meteorological Agency (JMA).

Based on surface observations over 30 years, the number of torrential rain events in Japan is increasing, he said. Seismologist Robert Geller, professor emeritus of the University of Tokyo, said it's likely to get worse.

"We should stop saying 'extreme' and face up to the fact this is probably the new normal," he said.

He added that while earthquakes themselves are unlikely to be impacted by climatological change, heavy rain can exacerbate landslides -- as seen in Hokkaido -- and make conditions much worse.

Bausch, an impact modeler who tries to predict the effect of natural disasters, said what he has seen in the last couple of years have "impacts that dwarf anything seen previously."

'Taken by surprise'

The flooding was one of the more alarming events of Japan's summer.

"Japan is a well-prepared nation, to get caught off guard and to have a number of fatalities probably took them by surprise," Bausch said.

The floods came as swathes of the country sweltered under scorching summer temperatures.

In Kumagaya, a city near Tokyo, the mercury rose to 41.1 degrees (105.98F), the highest ever on record in Japan, according to the Japan Meteorological Agency, almost 12 degrees hotter than average temperatures this time of year.

The effects of heat haze is seen during a heatwave in Tokyo on August 2, 2018.

Nearly 110 million of Japan's 128 million people were impacted by the heat wave, with roughly 90% of the country experiencing extreme heat, according to CNN meteorologist Derek Van Dam.

It is a phenomenon played out on a much wider scale, according to the US National Oceanic and Atmospheric Administration . This June was the fifth hottest June on record, the NOAA said, and all 10 warmest Junes have occurred since 2005, with the hottest ever in 2016.

Globally, the average land and ocean surface temperature for the first three months of the year was the sixth highest such period since global records began in 1880.

Fingers point to climate change

Disaster prevention experts say that while it is difficult to pin an exact cause on any one event, the trend of more frequent weather events points to climate change as the principal cause.

"If we go back far enough we can see things happening on these lines but globally we're definitely seeing more extreme events, because the oceans are warming; there's more moisture in the atmosphere," Bausch said.

He said, in addition to the increase in deadly events associated with hotter summers, winters are also becoming more extreme.

Japan has been somewhat shielded by the worst of the weather, due to its wealth and preparation.

"I think events like these would be catastrophic in countries like Myanmar, Bangladesh," Bausch said. "There have been, in recent history, tens of thousands of fatalities in events like these."

So what can be done?

Yamaguchi said that his agency was looking to change the warning systems' focus — from simply announcing the meteorological conditions to defining what the risks were -- for example warning of flood and landslides, rather than just warning of heavy rain.

"How to convey the (impact of this) meteorological information to the public is a challenge but we've made great progress," he said.

Disaster management agencies in Japan and abroad are learning each time there's a natural disaster.

"In 2011 the tsunami was bigger than expected, (there were) more fatalities and the evacuation areas and safe zones not big enough.

"(They) really under-designed for that. Everyone heeded that around the world, those lessons are learned both inside and outside Japan," Bausch said.