Taking advantage of our vehicle’s incarceration in a container somewhere in Santos I took a few days off from Atlantic Rising to go on holiday with my sister, Bryony. On Monday, our last morning in Rio we looked out across leaden skies as the rain fell on Rocinha, Rio’s largest favela.

“Top of the hills, great views, come on, it’s an excellent zip code”, our guide Colin enthused like an estate agent. 

Perched on the steep slopes above the affluent communities of São Conrado and Gávea, Rocinha is far from des-res. Where Rocinha’s roofs are flat to accommodate unplanned extensions, Sao Conrado’s roofs are home to turquoise swimming pools. In Rocinha tiny alleyways squeeze between honeycomb brick walls, seen from below, the favela is so crammed it looks like a wall of houses.

These are parallel worlds. The state is almost completely absent from the favelas. In its place drug gangs run by teenage traficantes impose control. Police raids, invasions by rival gangs and shootouts have led the Brazilian press to equate the violence of the favelas with official war zones. In October 2009 12 people were killed, including two policeman who died when their semi-armoured helicopter was shot down. 

When these worlds meet it is on unequal terms. The majority of the favelados, who account for about 20% of Brazil’s population, have nothing to do with the drugs trade but are discriminated against in the employment market, prone to police spot checks and witness to the horrific violence on their doorsteps. They provide the backbone of the informal service economy, they are the maids and waitresses in the wealthy bairros, the shoeshine boys and the men that hire out parasols and deck chairs on the fashionable beaches of Ipanema and Copacabama. 

As we walked around Rocinha’s labyrinthine alleyways the rain continued. It ran off the corrugated iron roofs, through the open sewers beneath our feet and poured from outflow pipes on the flat roofs. 

After our tour we returned to ‘the asphalt’, slang for the area beyond the favela. My sister left for the airport and I concentrated on catching the bus back to Santos. I took a taxi, giving myself 2 hours for what should have been a 30 minute journey. It had been raining all day and there were rumours of traffic jams. 

I was comfortably cocooned in the back, watching Rio’s lights melt with the raindrops on the windscreen, grateful for the drop in temperature, when we ground to a halt. Hazard warning lights and open bonnets suggested that some cars had already succumbed to the deluge. We made a u-turn in search of another route. Our hunt took us on a tourist’s trail of the city and I ticked off the destinations of the previous week from the back seat. But at every turn we were thwarted by immobile traffic or streets so deep in water that passage was impossible. And still it rained. 

With frustration came an increasing lawlessness. Traffic lights became less important, the direction of flow negotiable. Occasionally I jumped out to halt the cars so that we could squeeze through a gap or make a u-turn. I quizzed the driver about how far away we were. “No closer” came the inevitable reply. 

At midnight we gave up, pulling into a petrol station forecourt with the other embattled road users; police patrol cars with flashing red lights and tired taxi drivers shaking their heads through the windows of their yellow cars. I took shelter in a hostel and awoke early with fresh resolve to reach the bus station. 

But Rio had been transformed overnight. The rain had not abated and I marched out onto streets full of people standing under doorways looking at the sky. Those that braved the rain walked in columns down the pavement beneath an eclectic array of umbrellas. An old man passed me with just his sodden newspaper for shelter whilst others had donned binliners and plastic bags hats. 

I joined the crowds, trying to find transport to the bus station. But now I found whole streets flooded, cars slowly drowning and the water spurting from the drains like fountains. 

Eventually I found a taxi driver with mischievous eyes. After a circuitous drive, and one telly-tubby “uh-oh” moment when we stopped to contemplate the flood ahead of us, we made it through. And shortly afterwards I was carried away above the waters on the flyovers that lead out of the city. Only when I arrived in Santos did I realise the severity of the flooding. 

A record breaking 29cm of rain fell in less than 24 hours on Tuesday in Rio. So far 175 people have died as a result. The rain fell on both the affluent areas and the favelas. But it was in the slums such as Rocinha and the even less developed favelas, on steep slopes and unstable soils that the landslides and flooding were worst. We are now sitting in front of the television with the other residents of our hostel watching the desperate rescue effort unfold. And still it rains in Rio.