Smoke continues to billow in downtown Auckland 24 hours after fire broke out in the incomplete complex.

Shortly after 1pm yesterday came the first reports of a fire on the site of the SkyCity New Zealand International Convention Centre in central Auckland. That brought a massive mobilisation of emergency services, evacuations of surrounding buildings and closure of city streets. As the flames licked into Wednesday morning, officials and experts attempted to assess the severity of the impact – and the more immediate task of extinguishing the fire.

Here’s what we know so far, in Q&A form.

What is the latest state of the fire?

The work to snuff out the fire was ongoing at lunchtime Wednesday, with firefighters focusing on protecting the body of the building while allowing the roof to burn out. Dozens of firehoses were trained on the complex, while smoke continued to funnel out.

Shortly after 1pm, Fire and Emergency NZ said: “We plan to sacrifice the roof to allow firefighters better access to the fire and are working with the building engineers to make sure this is done safely.”

About 70% of the roof had burnt out as of 1pm.

Early afternoon there were more than 30 fire appliances and 100 firefighters and support staff onsite.

Overnight flames had leapt as high as 30 metres.

How long will the battle to tame the fire continue?

Fire and Emergency Auckland regional manager Ron Devlin this morning told RNZ the plan remained to prevent the fire from making its way downwards. “Everything is looking reasonably positive towards that,” he said.

“We’re going to be here all day and probably into the evening. It’s a big fire in a very, very large building.”

Just how big is it?

The New Zealand International Convention Centre is seven storeys high and measures the 32,000 metres squared, including a 300-room Horizon hotel and a “retail laneway” linking Nelson and Hobson streets. The main hall, according to SkyCity, will be able to host as many as 4,000 people, more than five times the capacity at the existing SkyCity convention centre.

What are the immediate risks?

The major risk would be the fire spreading from the roof to the floors below – avoiding that has been a focus of the firefighting effort, and so far appears successful. The roof itself was “sacrificed”, said Fire and Emergency Auckland, so that they could focus on protecting the main building.

There had been concerns that a crane towering over the site might overheat and topple, but as of this morning that risk was thought to have been greatly reduced.

For all the seriousness of the fire, there will be great relief that action was taken earlier in the year after the discovery of aluminium panels being used that were made of were the same materials that contributed to the Grenfell Tower fire in London.

What was the cause of the fire?

It’s too early to say with any certainty – and officials have resisted any invitation to speculate. Unconfirmed media reports suggest that an “unattended blowtorch” was responsible, but at least one expert has expressed scepticism about that version of events. There was no sprinkler system yet installed.

Investigations into the cause will be undertaken by both Fire and Emergency NZ and Worksafe.

What does it mean for surrounding buildings, roads, traffic and public transport?

The TVNZ building was closed on Wednesday morning, as were the Auckland District Court, the Central City Library and Chorus House.

The SkyCity precinct remains closed, with hotels likely remain closed tonight. SkyCity says its operations are on course for reopening tomorrow.

Cordons remain on surrounding roads, with some bus services affected. For more see Auckland Transport announcements here.

What is the latest advice to Aucklanders?

Auckland Council advises that all essential council services are still running, but staff have been asked to stay away from the city centre if possible.

The advice is to avoid the city unless absolutely necessary. Mayor Phil Goff said anyone in proximity to the fire could “feel the acridity in your throat, eyes and mouth, so it’s unsuitable conditions for workers”.

Anyone nearby has been asked to stay clear of the smoke, to close windows and doors, and turn off air conditioning. Anyone with breathing difficulties is urged to see a doctor.

What about injuries?

Mercifully, nothing serious has been reported. A firefighter was taken to hospital yesterday, but has since returned home.

Why aren’t we seeing helicopters dumping water on the thing?

Over to Fire and Emergency NZ: “Helicopters with monsoon buckets are a firefighting tactic predominantly used for vegetation fires and very rarely used for building fires … In this instance, it would not be effective to fight the fire with a helicopter due to the complex structure of the roof. Firefighters are able to direct water to where it can be most effective.”

What does it mean for that green glass wall?

Some photographs of the fire suggest the flames are in close proximity to the stained glass artwork by New Zealand artists Sara Hughes and Peata Larkin, which features more than 550 panels. Speaking to the Herald last night, however, Paul Baragwanath, who was involved in the commissioning of the work by SkyCity, the art was likely to survive unharmed.

How does it affect the schedule for completing the complex?

The project had already been put back by almost two years from its original timetable to an estimated opening of late 2020, as well as facing cost overruns. According to Goff, the fire could well further “put it back years”.

Fletcher Construction, who won the contract to build the Convention Centre, said there would be a “major delay” in construction, but that it would be completed.

As of today, the Fletcher Construction website still advises that it will open in 2019.

What about Apec?

There were real doubts, Goff suggested, that it would be ready to host the Apec summit in just over two years’ time. The event, for which the hosting role rotates around the Asia-Pacific member states, takes place in November 2021, and is expected to see 14,000 people visiting New Zealand.

What does it mean for SkyCity and Fletcher Construction?

SkyCity CEO Graeme Stephens called it “absolutely devastating” for all involved. Both companies took a knock on the share market, but advised that insurance was in place to cover the impact.

Were the materials used in the roof a problem?

It is too soon to say with any certainty, but experts have told The Spinoff that the straw-bitumen-plywood combination was not, as it might appear, unorthodox, and adheres with environmental priorities.

What impact does the weather have?

Strong winds, thunder and rain hit Auckland early today. That followed a MetService strong wind watch, which warned of gusts of up to 100 km/h. The conditions made the task even more hazardous for firefighters.