The incidents happened as a storm hitting the North Island started moving into the Hawke's Bay region. SH5 users called conditions on the road a "weather-bomb".
A forecast by national meteorological agency MetService for Hawke's issued about 9am was for strong northerly and gales gusting up to 90 km/h in exposed places, turning northwest and easing during the evening Rain was forecast about the ranges, with heavy falls, spreading elsewhere in the afternoon, then clearing late evening.
A "strong wind watch" notice had been issued for much of the North Island, including Hawke's Bay, and highways manager Waka Kotahi New Zealand Transport Agency warned of the conditions on SH5, with particular notice to for special care with high-sided vehicles and motorcycles.