[thunderous explosion] -[Narrator] Sixty-six million years ago, the ferocity of Mother Nature brought an end to the reign of dinosaurs.

But these days, it's helping to reveal them.

Today palaeontologists Henry Sharpe and Mark Powers are on the hunt for the largest group of Tyrannosaurs ever discovered, Albertosaurus.

-[Mark Powers] We are boots on the ground looking for possible finds and usually what we're finding is just something slightly poking out of the hill.

-[Henry Sharpe] Everything can be found here.

You just got to spend enough time looking.

[mysterious music] -[Narrator] The art of dino prospecting has changed little in more than a century.

Time, patience, determination, and some luck.

Over time, nature's elements have combined to help erode the rock and expose these buried dinosaurs once more.

And it was while simply patrolling these hills that Mark and Henry made a spectacular discovery.

-[Henry] It was at the end of the day, we're tired, we hadn't found anything.

-[Mark] But to motivate ourselves, we kind of just kept saying, "One more sandstone, one more sandstone."

-[Henry] Eventually we got to one layer where we spotted some bones kind of eroding out of the hillside.

And as Mark was kind of standing up to look and see how far it went in either direction, I happened to look down at his boots and he's standing on what ended up being Rose's femur.

-[Narrator] They had stumbled upon the leg bone of an Albertosaurus, but they soon realize there was much more here.

Lying just below the surface was the remarkably complete skeleton of a teenage Tyrannosaur they named... Rose.

-We found the tibia was still connected to it.

And then as we explored that, we found that the foot was still there.

So everything was just together and just more and more bones were popping up.

-[Narrator] Including a piece of her skull, which could help give greater insights into how these predators hunted.

[Tyrannosaurs booming] Albertosaurus were ferocious carnivores and, terrifyingly, appear to have hunted in groups.

[growling, huffing] It's thought that the faster juveniles like Rose would have used their speed to flush out prey, driving them into the stronger jaws of the waiting adults.

-[Henry] Really nice fossils, especially of a tyrannosaur like Albertosaurus.

They're super, super rare.

When you get to find those, [contented sigh] it's the greatest feeling in the world.

[tapping with hammer] -[Narrator] But that feeling can be fleeting.

Because the weather that helped reveal Rose is now her biggest threat.

Exposed to the elements for the first time in over 70 million years, these fossilised bones are prone to erosion and degradation; needing to be protected at all costs or being lost forever.

But before the team can safely remove Rose's skeleton, the weather takes an alarming turn.

[wind howling] With escalating winds and a lingering tornado warning, the team is forced to abandon Rose.

-[Woman] Everybody, hold onto your hat.

-[Narrator] They do their best to protect their fragile discovery.

-[Woman] Get the rest of the quarry covered and everything.

[plastic rustling] -[Man] No, I don't think it can hold it.

-[Woman] Put a rock on top, and rocks around.

-[Henry] Yeah.

-[Man] Okay.

Let’s get the heffle outta here.

-[Henry] If we found a bit of the skull, it’s means Rose is going to [indistinct] -[Man] Screaming at us.

-[Narrator] They retreat down to basecamp.

[wind howling] -Winds up to 90 kilometres an hour are strong enough to pull shingles off of roofs.

I mostly think it's just safer to vacate.

-Yeah.

-We've never had anything like this in all the years we've been doing this, and now it's all happening all at once.

-And if all this is for a tyrannosaur with no skull, I don't know what I'm going to do.

Smile through the tears.

Yeah.

-[Woman] We should vacate sooner than later.

-[Man] Fun.

-Fun.

Field work is so much fun.

Why do we do this?

-[Narrator] The team shelters for the night.

But as for Rose up on the mountain, all they can do now is hope for the best.

The next morning, the skies have cleared.

[indistinct chatter] But has the vital fossil evidence survived the night?

-[Woman] All right, let's see if it lived.

This looks like it could have filled up with the water.

-[Henry] Okay.

-[Woman] Yay!

-[Narrator] The team can now set to work, trying to extract this precious skull fragment.

But with last night's chaos fresh in their mind, they know they have to act fast.

The weather can be a fickle friend to palaeontologists.

Without it eroding away the rock and earth beneath our feet, the stories of dinosaurs could remain untold forever.

But the joy of discovering a dinosaur skeleton offers no guarantee that it will survive a second extinction at the hands of the very same elements that helped uncover it.