As I pedalled home along the highway, I realised that something was wrong. The sky was dark and threatening, and the light had taken on a peculiar green hue. The wind had gone, leaving behind a heavy scent of electricity and an unnatural silence from the now-still fields of corn. I stopped by the side of the road to look around.

Somewhere out towards the featureless horizon I could just about see the buildings of my aunt's farm. Maybe a mile away - almost invisible against the darkening sky - were the metal tower and concrete bunker of a phone relay station. Beyond that there was nothing; nothing that would account for the feeling of nervous dread that I just couldn't shake.

I felt movement from my backpack and heard a canine whimper. It was Totty. Whatever it was that was making me nervous was also bothering him. I took off the pack and held it against my chest, trying to comfort my pet. "Hush," I said, trying to sound reassuring. "Be quiet, Totty. Dodo's here." But it didn't work. Totty squirmed and whimpered again, his attention fixed on something just behind me. I turned to look.

There was a new cloud on the horizon: dusty yellow, with stripes of ochre swirling around inside it, a writhing strip of darkness at its heart. I watched the cloud for a moment, fascinated by the dancing colours, before I worked out what it was.

Twister. Deep breath. What to do? Twister! It was getting bigger, coming this way. TWISTER! Oh God!

I had to find shelter. The farm was too far away. The storm would catch me before I was even halfway there. What about the relay? If I could get there in time, maybe I could break in and wait for the tornado to pass. I had to try - God only knew what would happen to me if I didn't!

I pedalled hard, almost spilling myself on the gravel as I turned off the road. The gate in the chain fence was open, a phone company pickup parked just past it. I ditched my bike and stumbled into the bunker.

"Hey!" I heard a man shouting, and I saw a tousle-haired head peer out from between the equipment racks. "You shouldn't be - !"

"Twister!" I shouted. "Comin' this way!" I tried to close the bunker door, pushing hard against it.

The man ran towards me, trying to stop me. "No you don't!"

""Twister comin'!" I shouted again. "Look!" I pointed out of the bunker. There, no more than a mile away now, was a black, twisting column that stretched between the ground and the sky. A sudden wind blew up, dragging everything loose out of the bunker and towards the dark funnel of cloud. The man swallowed, then threw himself against the bunker door, slamming it hard into its frame.

I staggered backwards, collapsing in a corner. A scrabbling against my back reminded me about my dog. I twisted around, taking off my pack. Totty looked up at me. "We'll be safe now," I told him. Totty yawned and licked my face.

The man sat down beside me. "Thanks. I didn't see that."

I pulled out my phone. "I thought there was meant to be a warning."

"System's down," the man said. "Just bad luck that it happened now. I'm supposed to - ."

A deep-throated roar shook the bunker. It started off as a harsh growl, then grew in strength, changing from a noise into an irresistible pressure. The bunker creaked and groaned, and then the lights went out! I threw myself towards the maintenance man, grabbing at him in panic. The roar of the storm grew louder, pulling the air from my lungs. I tried to breathe, but I couldn't. I screamed and - !

It was dark, still, quiet. I took a deep, sobbing breath. Still alive. Good. The bunker seemed to settle, and I could smell a mixture of dusty concrete and cheap aftershave.

"That was intense," the man said.

I let go of him and shuffled backwards until I could feel the edge of an equipment rack through my jacket. "Yeah." I gave an awkward laugh. "Never felt anything like that before."

There was a click, and shaft of bright light lit the man's face from below. "Alright. Let's see what's happened." He swung his torch beam around the bunker's interior, flicking it over the shelves of dead electronics. "Looks fine. Stay here."

He got up. I watched him stumble towards the bunker door, then pull it open to let in a shaft of pale blue light. The man stood there for a moment, silent, before saying just one word. "Shit."

I hauled myself to my feet and went to take a look. The light blinded me for a moment, making me squint. "I guess we're not in Kansas any more," I said.