Summer Storms
Summer storms can arrive quickly bringing strong winds, heavy rain, hail, lightning and rough seas. They can bring down trees and powerlines, damage homes and vehicles and disrupt travel and access.
Summer storms are often less predictable and can come with shorter warning times. Learn more about the risks and how you can take a few simple steps to prepare ahead of time.
While thunderstorms can be forecast ahead of time they are also highly unpredictable and often develop suddenly with little or no warning. They affect very localised areas over a short period of time.
Thunderstorms can bring:
- Torrential rain (>25mm per hour) causing dramatic surface flooding, reduced visibility and rapidly rising rivers and streams
- Large hail up to 2cm in diameter that can damage roofs, windows, vehicles and livestock
Lightning - Strong, gusty winds (>110km per hour) that uproot trees, break branches and damage powerlines, and send outdoor furniture and trampolines flying. Occasionally this can cause a tornado
- Heavy rain causing surface or deeper flooding
MetService issue two types of advisories when they see potential for thunderstorms:
- A yellow severe thunderstorm watch – stay alert. These are issued up to 12 hours before a potential thunderstorm
- A red severe thunderstorm warning – act now. This is when a thunderstorm is detected up to 60 minutes before the storm reaches you or with only minutes notice
There’s no orange thunderstorm warning due to the nature of thunderstorms.
Tropical cyclones and their remnants can be a serious risk to people and property, sometimes causing extreme and widespread damage. They can bring:
- Heavy rain causing flooding and potentially landslides
- Gale force winds (63km/h or more) that uproot trees, break branches and damage powerlines causing widespread power outages
- Thunderstorm activity
- Rough seas impacting boats and causing coastal erosion and inundation
Tropical cyclone season in the Southern Hemisphere usually runs from November to April, peaking in February.
Tropical cyclones form over warm ocean waters in the South Pacific and Australia. As they move towards the cooler waters of New Zealand, they lose some of their tropical characteristics, known as extratropical transition. It is no longer classed as a tropical cyclone and has no category,however it can still be a powerful and potentially damaging storm. MetService now refers to these systems simply as Cyclone [Name].
Auckland Emergency Management works closely with MetService to stay informed and ready to respond to incoming tropical cyclones.
Learn more about Tropical cyclones and their monitoring in New Zealand on the MetService website.
How to be summer storm ready
Before a storm: Plan and stay safe
- Stay informed: Keep up to date with weather forecasts and warnings from MetService
- Get your home ready ahead of time:
- Make trees more wind-resistant by removing diseased or damaged branches
- Clear away leaves and debris from gutters and drains to help reduce flooding or water damage
- Secure outdoor furniture, trampolines and loose items
- Green waste and tree removal services may be unavailable just before a storm, so do this regularly instead of waiting for severe weather
- Ensure your home and contents insurance is adequate and up to date
- Be ready for power outages:
- Have torches, spare batteries, a battery-operated radio and a full gas bottle for your BBQ
- Make an alternate plan if you rely on power for medical needs, pumps or septic systems
- Prepare your household emergency plan: Make sure family, friends and flatmates know what you’ll do in case of an emergency
- Check your emergency supplies: Ensure you have at least three days of water and food supplies
Travelling during the summer storm season
Make a plan if you’re travelling over summer:
- Tell someone where you’re going and when you expect to return
- Consider packing a small emergency kit/grab bag
- Stay informed with weather forecasts and warnings in your location
- If an emergency happens, follow local Civil Defence advice in the area you’re visiting
When severe weather is forecast
- Secure loose outdoor items, clear gutters and drains
- Bring pets indoors. Storms can be unsettling and they are safer with you
- Ensure livestock aren’t sheltering under isolated trees or other objects that could attract lightning
- Moor boats securely or move to a designated safe location
- Secure boat trailers using rope, chain or tie-downs anchored to the ground or a building
What to do during a storm
- Stay informed
- Follow the latest weather forecast and warning
- Keep updated on advice from Auckland Emergency Management and emergency services
- Secure your whare/home and critical buildings
- Close windows and shutters if you have them
- Pull curtains and blinds closed to reduce injury from flying glass if a window breaks
- Close internal and external doors to limit wind damage
- Take extreme care with items that may conduct electricity if your whare/home is struck by lightning
- Look out for falling or damaged trees, damaged roads and debris and fallen powerlines. Always treat powerlines as live
- If driving conditions are dangerous, safely pull over away from trees, drains, low lying areas and floodwater
- Drive to the conditions
- Do not drive through flood waters
What to do after a storm
- Check that you, your whānau, neighbours and property are safe. Check on older people or those who may need extra support
- Stay safe by avoiding dangerous hazards- floodwater, debris, damaged roads, fallen trees
- Stay away from downed powerlines and always treat them as live
- Drive to the conditions and do not drive through flood waters
- Report fallen trees, blocked drains or debris on public property to Auckland Council online
- Check your home and property for damage
- Take photos of damage and contact your insurance company
- If you rent, contact your landlord and your contents insurance provider
- Clean up any storm debris safely