Typhoon Jebi is raking through the coast of Japan and the major cities of Osaka and Kyoto – while avoiding a direct hit on capital city Tokyo.
Honshu’s population of 127,185,332 is now at risk, as more than 1 million people have been ordered to evacuate to nearby shelters.
Conditions have meant the island is all but cut off from a quickly advancing shoreline and localised flooding.
And high winds have meant about 700 flights have now also now grounded, so people visiting for a holiday or seeing family could be trapped while the storm rages.
What should you do if you are visiting Japan?
A total of 700 flights and counting have now been cancelled as Jebi prompts storm surges and quickly advancing tides into nearby airports.
High winds expected to push the 135mph mark will develop in the near future and more flights are likely to be dropped as a result.
A massive 2,591-tonne tanker was also sent crashing into a bridge connecting Osaka’s Kansai airport, which is n ow almost completely under water.
Major infrastructure has now been abandoned in some places, as some 144,000 people are left without power, and the Tokyo and Hiroshima Shinkansen bullet train services are suspended.
Popular tourist destination Universal Studios Japan has even been closed as it braces for the onslaught of extreme weather.
Expected to continue until September 5 at least, the storm will see many people trapped, with Tokyo Haneda, Tokyo Narita, Nagoya Chubu and Osaka kansai airports all shut.
People are advised to check airport websites for updates on flight rescheduling or refunds.
The UK Foreign Office also released advice to people in Japan unsure about how to progress in the situation.
Japan is no stranger to extreme weather or flooding, being in the midst of Pacific hurricane season each year, and having recently sustained heavy flooding in July.
The UK government advises the best way to stay on top of news for Brits abroad is to follow the British Embassy Tokyo on Facebook and Twitter.
While a lot of Japanese media will also be in the native dialect, the radio stations of Inter-FM at 76.1 and Yokohama FM at 84.7 are English speaking.
Advice is to stay in tune with as much of the Japanese media as possible and the Japanese Meteorological Agency will provide rolling updates.
The service is also built for english-speakers who can keep in touch with real-time updates as the storm fans out.
Japanese officials will also issue evacuation notices, which could require people to take to nearby shelters until the storm passes.
Each region in Japan and municipality in Tokyo is equipped with at least one shelter, and in Tokyo alone can house more than 3 million people.
As a category 4 storm, damage could be catastrophic, so preparation will be vital in the coming days.
Those unable to make it into a local shelter or out of the affected areas in time will ned to ensure their residences are protected.
Like hurricane season in the USA, residents have been prompted to board up their homes with planks of wood and prepare emergency kits.
As many people are now without electricity, other utilities may be dropped in the near future, this means that keeping a good supply of water is essential in order to stay alive.
A typhoon survival kit is also a good idea, including food supplies and a hazard map, easily procurable online or at nearby offices.
Any loose objects outside of a residence should be tied down to prevent damage as strong winds are liable to pick up and cast items into homes or the streets.