The transport chaos and the number of deaths following the unprecedented snowfall that dumped on Japan is now being blamed on the Japan Meteorological Agency. The agency decided against issuing a Heavy Snow Emergency Warning because it claimed the snowfall did not meet the standards for such a warning.

According to the Yomiuri Shimbun, the agency's outdated warning systems has resulted to 19 deaths, more than 1,600 injured, as well as the massive transport mayhem in Japan.

Weather forecasters had advised residents in the region around Tokyo to brace for more snow later this week.

Yomiuri Shimbun said JMA only issues warnings regarding heavy snow if the forecast meets its criteria of "when the depth of snow is predicted to be a value observed once every 50 years for a prefecture-scale area."

Another requirement that must be met before a warning can be issued is that "warning-class snowfall continues for almost a whole day or more."

The depth of snow in Kofu reached 41 centimetres on Friday evening, meeting the agency's "once every 50 years" benchmark. On Saturday morning, the snowfall stopped, with total accumulation recorded at 114 centimetres.

"We judged the snowfall didn't meet the standards [for warning issuance] because [the warning-class snowfall] was not predicted to continue for a whole day as of Friday evening," the Yomiuri Shimbun quoted an unidentified JMA representative.

For the longest time, JMA patterned its warning issues based on past heavy snow disasters, with origins mainly coming along the Sea of Japan. But the current snowstorm came from a "southern shore low pressure system" that moved northeast over the south coast of the Japanese archipelago.

"Cities that rewrote their snowfall records included Kofu, Yamanashi Prefecture, which was bombarded by 114 cm, Maebashi, Gunma Prefecture, which got 73 cm, Iida, Nagano Prefecture, with 81 cm, Kumagaya, Saitama Prefecture with 62 cm, Shiroishi, Miyagi Prefecture, with 42 cm, and Utsunomiya, Tochigi Prefecture, which saw 32 cm," the Japan Times reported.

The agency maintained it is rare that southern shore low pressure will trigger a snowfall for long periods of time in the same region.

"[The agency] will have to consider revising [the warning] standards for each area in a flexible way, by not adopting the same standards for snowy areas and areas that experience little snowfall," Naoya Sekiya, an associate professor at Toyo University, said.

Most often, Japan's local governments will only alert residents when the JMA issued formal warnings.

Apart from the number of dead and injured, the Yomiuri Shimbun reported more than 6,900 people have been trapped as snow blocked roads and railway lines. Deliveries of gasoline have likewise been delayed to some petrol stations because of the impassible roads.