Japan’s Deep Snow Turns Deadly as Sudden Thaw Triggers Avalanches and Flooding

Record-breaking winter storms have blanketed northern and western Japan in recent weeks, and now authorities are warning that the greatest dangers may arrive not with more snow, but with the thaw. As temperatures begin to climb in early February 2026, Japan’s government and meteorological officials are sounding the alarm over snowmelt-induced floods, avalanches and a rising toll of snow removal accidents in communities where drifts as high as two metres are only just starting to soften.

From Deep Freeze to Sudden Thaw

Since late January, a persistent mass of cold Arctic air has swept across the Japanese archipelago, feeding intense snow bands along the Sea of Japan. At least 15 prefectures, including Aomori, Niigata, Akita, Yamagata and Hokkaido, have spent days under near-continuous snowfall. In some of the hardest-hit towns, residents have moved through canyon-like corridors carved between walls of snow that rise well above head height.

As the storms persisted, snow depth in parts of Aomori climbed to around 1.7 metres, one of the highest readings in roughly four decades according to the Japan Meteorological Agency. Similar scenes unfolded across the Hokuriku and Tohoku regions, where roofs disappeared under thick white caps and rural homes, greenhouses and outbuildings strained under the load.

Now, however, the weather pattern is shifting. Temperatures in some northern cities have abruptly risen above freezing, reaching about 8 degrees Celsius in Aomori during the first week of February. While this respite may be welcome for those exhausted by shovelling and travel disruption, the sudden thaw is precisely what has officials most concerned. Water-laden snowpack, liquefying ice and clogged drainage systems are combining to create ideal conditions for avalanches, roof collapses, flash flooding and treacherous ice.

Deputy Chief Cabinet Secretary Masanao Ozaki and other senior officials have urged residents to stay away from steep, snow-loaded slopes and to remain vigilant around their homes. The warning is stark: the transition from winter’s deep freeze to springlike warmth can be every bit as dangerous as the storm itself.

Rising Death Toll From Snow and Ice

Behind the government warnings lies a mounting human cost. Since heavy snow began around January 20, at least 35 people have lost their lives and nearly 400 have been injured nationwide in snow-related incidents. Many of the fatalities occurred far from ski resorts or remote mountain passes. Instead, they took place on residential rooftops, narrow farm roads and village driveways as residents tried to dig out.

Niigata Prefecture has reported the highest number of deaths, followed by several northern prefectures where deep drifts are part of life each winter. Typical tragedies involve elderly residents climbing onto roofs to clear snow and then losing their footing, or being struck by heavy slabs of packed snow sliding suddenly from eaves. In some cases, garages or single-story homes have collapsed under the cumulative weight, trapping those inside.

The Fire and Disaster Management Agency has stressed that many of these accidents are preventable. Each year in Japan, dozens die during snow removal, a statistic that spikes during particularly severe winters. Officials recommend that residents work in pairs, wear helmets and fall-prevention harnesses, and avoid climbing onto roofs altogether if possible. Yet in rural communities where professional snow removal services are scarce and roofs must be cleared to prevent structural failure, these guidelines can be difficult to follow in practice.

With warming temperatures loosening the snowpack, the nature of the risk is changing. What was once stable, albeit heavy, powder is turning into dense, wet slabs that can break free with little warning. For rescuers, the challenge is compounded: unstable snow can impede access, while thaw-induced flooding and hidden ice complicate every response.

Avalanche Threat in Mountain and Ski Regions

Japan’s famed powder snow and steep alpine terrain are a powerful draw for domestic and international travelers, particularly in Hokkaido and the Japan Alps. This season, however, the same conditions that appeal to skiers and snowboarders have created a hazardous avalanche environment. Sustained snowfall has built up thick layers on mountain slopes, and the recent warm spell is now destabilising those layers.

Authorities have issued specific avalanche advisories for northern and mountainous regions, including parts of Hokkaido, Aomori, Iwate, Yamagata and Nagano. Sudden temperature increases are known to weaken the bonds between snow layers, allowing wet, heavy snow to slide en masse. Even smaller avalanches or cornice collapses near ridgelines can be deadly for backcountry enthusiasts traversing popular routes just beyond resort boundaries.

Local governments and ski areas have responded with temporary closures of certain trails, increased patrols and controlled blasting in some high-risk zones. Visitors are being urged to heed rope lines and official signage, avoid entering off-limits terrain and check the latest avalanche bulletins before venturing out. Mountain rescue teams, many staffed by experienced volunteers, are on heightened alert as school holidays and long weekends bring more people to the slopes.

For foreign travelers, the danger can be compounded by unfamiliarity with Japan’s terrain and snow conditions. Tour operators and local tourism boards are stepping up multilingual safety messaging, emphasising that even experienced skiers should not underestimate the impact of rapid warming on a deeply loaded snowpack.

Snowmelt, Flooding and Hidden Hydrological Risks

Beyond the immediate threat of avalanches, the current pattern of heavy snowfall followed by abrupt warming poses significant hydrological risks. As thick layers of snow melt in a short window, large volumes of water are released into rivers, streams and urban drainage systems that may still be choked with ice and snow. This increases the likelihood of localised flooding and ice jams, particularly in low-lying communities and along smaller tributaries.

In many northern towns, snowploughs have created towering roadside embankments. When temperatures rise, meltwater from these piles can pool on road surfaces, refreezing overnight into black ice that catches drivers unaware. Storm drains buried under compacted snow are slow to reopen, meaning that water may seek alternate paths through basements, underground passages and rail underpasses.

River authorities and local governments are closely monitoring water levels in snow-fed catchments. While the heaviest concerns at the national level often focus on typhoon season, winter and early spring snowmelt is an established contributor to Japan’s complex flood risk. In recent years, climate variability has increased the occurrence of abrupt temperature swings, making it more common to see a rapid shift from blizzards to springlike warmth in a matter of days.

For residents and travelers alike, officials recommend paying close attention to local advisories, especially in areas with a history of landslides or river flooding. Simple precautions such as relocating vehicles from low-lying car parks, clearing snow away from building foundations and ensuring that gutters and drainpipes are unobstructed can make a meaningful difference as the thaw progresses.

Why Snow Removal Becomes More Dangerous as It Warms

One of the subtler messages emerging from Japan’s winter safety campaigns is that snow removal does not necessarily become safer when temperatures edge above freezing. In fact, the opposite is often true. Fresh, powdery snow is comparatively light and easier to move, even if it accumulates quickly. As it compresses and absorbs meltwater, however, the same volume can weigh many times more.

For the individual on a rooftop or balcony, this shift translates into heavier shovelfuls, faster fatigue and a greater risk of muscle strain or sudden loss of balance. Wet snow adhering to boots and clothing also makes surfaces slick, increasing the likelihood of slips. On pitched roofs, melting snow can suddenly release in cohesive slabs, sweeping workers off their feet and over the eaves if they are not secured.

Officials urge residents in heavy-snow regions to adopt a more cautious mindset during thaws. Strategies include working shorter shifts with frequent breaks, using tools designed for pulling snow from the ground rather than standing on roofs, and enlisting neighbours or community volunteers so that no one works alone. In some municipalities, local authorities and the Self-Defense Forces have been dispatched to help clear key roads, school entrances and public facilities, easing the burden on vulnerable households.

The broader message is clear: as climate patterns bring more stark contrasts between cold snaps and warm spells, traditional assumptions about when it is safe to clear snow need to be reconsidered. What may have been routine work in the past can quickly turn hazardous under today’s more volatile conditions.

Impacts on Transport, Tourism and Daily Life

Heavy snow followed by rapid warming has strained transportation and daily life across large swathes of northern Japan. During the height of the storms, major highways and local roads were periodically closed, train services were suspended and domestic flights were delayed or cancelled. Even as ploughs have reopened main arteries, thawing conditions are creating new challenges for road maintenance crews and drivers alike.

In cities such as Aomori and Niigata, commuters navigating narrowed streets must contend with slushy ruts during the day and icy patches after sunset. Parking remains scarce where snowbanks still occupy curb lanes, and pedestrians pick their way along makeshift corridors between encroaching drifts. Schools and some businesses have adopted flexible schedules, remote learning and telework arrangements to reduce the need for travel on the most hazardous days.

For the travel industry, the situation is complex. On one hand, deep snow has delivered excellent conditions at many ski resorts, drawing enthusiasts despite the disruptions. On the other, concerns about avalanches, road closures and snow removal accidents have led some travellers to postpone or modify their plans, particularly in smaller onsen towns and rural areas where infrastructure is more fragile.

Tourism officials are working to balance promotion with safety messaging, highlighting the importance of travel insurance, flexibility and close attention to local advisories. In major hubs such as Sapporo and Nagano City, visitor information centres and hotels are keeping guests updated on lift operations, road conditions and recommended precautions when walking or driving.

Preparing for Future Winters in a Changing Climate

Japan’s current snow crisis is unfolding against a backdrop of longer-term climate questions. While global warming is associated with rising average temperatures, it can also contribute to more extreme precipitation events, including intense snowfall, when cold air masses interact with moisture-rich air over the Sea of Japan. The result is a pattern of winters that are sometimes milder overall, yet punctuated by short, severe cold waves and heavy snowstorms.

Experts note that this combination of variability and intensity poses particular challenges for disaster preparedness. Infrastructure designed for a more predictable snow season may struggle under sudden loads, while communities might be caught off guard by late or early-season storms. When those storms are followed by rapid warming, the compounded risks of avalanches, floods and structural failures are magnified.

In response, national and local authorities are examining how to adapt building codes, update hazard maps and refine early warning systems. Investments in more resilient power lines, snow-resistant structures and flexible public transport operations are part of the discussion. Community-level initiatives, from neighbourhood snow-removal cooperatives to expanded volunteer rescue training, are also seen as vital components of a broader resilience strategy.

For travellers to Japan’s snow-prone regions, these developments underscore the importance of approaching winter visits with an informed and flexible mindset. Understanding that conditions can change quickly, respecting local guidance and giving priority to safety over itineraries can help ensure that the country’s spectacular winter landscapes are experienced without adding to the seasonal toll of tragedy.

Staying Safe as the Thaw Continues

As February progresses and the balance between snowfall and snowmelt shifts day by day, Japan’s message to residents and visitors remains consistent: vigilance must not wane with the end of the storm. The period when snow begins to recede is one of heightened, not diminished, danger, whether from avalanches in remote valleys or blocks of ice tumbling from urban rooftops.

Simple measures can make a critical difference. Avoiding unnecessary time under eaves and power lines, checking updated avalanche and weather advisories, and using designated paths instead of ad hoc routes through snowfields all reduce exposure to the most common hazards. Those assisting with snow removal should utilise safety gear, work with partners and know when to stop and seek help rather than pressing on alone.

For policymakers, the events of this winter will likely serve as another data point in the evolving story of how Japan manages its complex relationship with snow, water and climate. For communities on the ground, however, the focus in the coming days remains immediate: getting through the thaw safely, supporting neighbours at risk, and learning practical lessons that can be applied when the next heavy snow inevitably arrives.

In the meantime, the country’s northern regions are caught in a delicate transition, as the deep snows that once symbolised winter’s grip begin to reveal the contours of an early spring. Whether those emergent landscapes become scenes of renewed activity or further disaster will depend largely on how carefully residents, travellers and authorities navigate the hazards of snowmelt in the weeks ahead.