With strong winds, drenching rain, high surf, and coastal flooding, Typhoon Lionrock made landfall in the Tohoku region of Japan Tuesday evening local time, near the city of Ofunato in Iwate Prefecture, according to an advisory from catastrophe modeling firm AIR Worldwide.
Arriving a week after typhoons Mindulle and Kompasu also struck Japan, Lionrock – which had the intensity of a Category 1 hurricane – brought extreme levels of rain to eastern and northern Honshu, Japan’s major island, which has resulted in landslides and flooding, AIR said.
“Typhoon Lionrock, which came ashore about 500 kilometers (310 miles) northeast of Tokyo, was downgraded to a tropical storm as it moved inland,” said Dr. Anna Trevino, senior scientist at AIR Worldwide. “Lionrock should cross the Sea of Japan by the end of the week and bring heavy rain to Russian maritime territory and northeastern China.”
Lionrock is the first typhoon to make landfall on the Pacific side of the Tohoku region since the Japan Meteorological Agency (JMA) began recordkeeping in 1951 and it is the fourth typhoon to make landfall in Japan in 2016. It hit the same area devastated by a 9.0 earthquake and tsunami in 2011, which caused massive damage to the Fukushima Dai-Ichi nuclear power plant.
Typhoon Lionrock made landfall at high tide, exacerbating storm surge and resulting in flooding in many coastal areas, said Trevino, adding that high wind from the storm brought down power lines throughout the region, resulting in as many as 10,000 homes being without power.
“Lionrock is expected to cause much greater damage from the inundating rain than wind. By Tuesday evening, the JMA had reported that 15 centimeters (6 inches) of rain had fallen in the region, and some areas across Honshu were projected to receive as much as 8 centimeters (3 inches) of precipitation per hour,” she continued.
“Some areas of the Tohoku region were projected to receive as much as 35 centimeters (14 inches) of rain by Wednesday morning, more than they normally would see in a month,” she went on to say.
According to news reports, nine people died at a nursing home in Japan’s northern Iwate prefecture as a result of flooding in the area.
Landslides – a constant risk in Japan – already have shut down roadways and affected travel and remain a thread of additional damage, AIR said.
In anticipation of the Lionrock’s landfall, upwards of 170,000 people were affected by evacuation orders, according to the Fire and Disaster Management Agency. In addition, more than 100 flights were cancelled in and out of the northern region of Honshu, and some bullet train services were discontinued, said the advisory from AIR.
“Tokyo Electric Power Co., which operates the heavily damaged Fukushima Daiichi Nuclear Power Plant, rushed to stabilize equipment, suspended some decommissioning, and began to closely monitor groundwater levels and seawater quality,” said AIR.
According to AIR, Japan has strict and well-enforced construction codes, although many existing structures predate the existence of these codes.
Residential exposures in Japan are dominated by wood construction; non-wood residences primarily consist of steel and concrete. “Modern wood construction typically demonstrates the best performance in typhoons among all wood constructions in Japan. However, damage to roof coverings and windows can allow wind-driven rain to enter and cause extensive damage to contents,” AIR said.
Larger multi-family apartment buildings and commercial and industrial structures are generally engineered and made of reinforced concrete or steel. “Complete structural collapse of engineered buildings due to typhoons is extremely rare; damage is usually confined to nonstructural components, such as mechanical equipment, roofing, cladding, and windows.”
However, a significant portion of Japan’s industrial stock is of non-engineered light metal construction, which is one of the construction types most vulnerable to high winds, AIR explained.
“[E]ven with modern flood-control structures, the risk of flood damage remains high in Japan. For a given flood depth/effective surge depth, a residential wood frame building generally will sustain more damage than a residential masonry building,” the AIR advisory said.
“Concrete construction is less vulnerable to flood than steel or masonry. Commercial and apartment buildings usually have stronger foundations than residential buildings, and are thus better able to resist flood loads,” AIR said, noting that water damage to machinery and contents drives most flood-related losses.
Also, because damage is usually limited to the lower stories of a building, high-rise buildings will experience a lower damage ratio than low-rise buildings as a smaller proportion of the building is affected, the company continued.
“In Japan, wind damage is typically automatically covered under standard fire insurance policies, but flood damage is not, despite the fact that Japan regularly experiences ‘wet’ storms that deliver extreme precipitation and flooding that contribute substantially to damage,” AIR explained.
Source: AIR Worldwide
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