Cascading Reels Slots: How Cascades, Tumbles & Avalanches Work
A cascade is what happens when a slot clears winning symbols, fills the gaps and checks the new screen for another win. If the replacements make another qualifying win, it can happen again, all within the same spin.
Gonzo’s Quest calls it an Avalanche, while Gates of Olympus uses Tumbles. The names are different, but the familiar remove-and-refill loop is much the same.
What are Cascading Reels?
You’re still in the same spin or round while this happens. A fresh screen of symbols doesn’t mean another paid spin has started, and every win along the way still counts.
How do Cascading Reels work?
The basic order is win, remove, refill, check again. In Gates of Olympus, a regular-symbol win starts the Tumble Feature. Winning symbols disappear, the remaining ones fall, and new symbols drop in from above. If the new screen produces another regular-symbol win, the process continues.
Gonzo’s Quest, a NetEnt game that’s been hugely popular in UK lobbies for years and a super game, calls it an Avalanche. A winning payline is paid before its symbols are cleared, then replacements fall into place without another stake. Some games only show you the total at the end of a sequence, but each win along the way still counts.
Reactoonz runs the same loop on cluster wins across its 7×7 grid: the winning symbols go, new ones fall into the gaps and the grid is checked again.
Pick any two games in the Face-Off to compare how their cascades work.
Compare how two slots use Cascading Reels
Choose two games to see what triggers a cascade, how symbols are replaced and what happens next.
At a glance
| Gonzo's Quest | Bonanza Megaways | |
|---|---|---|
| What starts it | A winning bet line is present after the symbols settle. | After a winning combination is resolved. |
| How symbols change | Winning symbols explode and new symbols fall into place without another stake. | Winning symbols are removed; replacements drop in from above, and the cart reel above reels 2–5 moves right to left to supply more. |
| How the sequence develops | New winning lines keep the Avalanche going until no win remains. NetEnt states no fixed limit on the number of Avalanches. | The Reactions continue while replacement symbols form further wins during the same spin or Free Spin. |
Explore each cascade feature
Most cascades remove winning symbols and refill their spaces, allowing another win to be checked without a new paid spin. Some games refill from more than one direction, expand the grid or let special effects trigger the sequence. The comparisons describe how each game actually handles the removal, refill and follow-up evaluation.
Gonzo's Quest
Cascade featureAvalancheBase game and features
- What starts it
- A winning bet line is present after the symbols settle.
- What happens to the symbols
- Winning symbols explode and new symbols fall into place without another stake.
- How the sequence develops
- New winning lines keep the Avalanche going until no win remains. NetEnt states no fixed limit on the number of Avalanches.
- Important detail
- The sequence can occur in a paid game round or a Free Fall; a new round or Free Fall begins a new sequence.
Sources: NetEnt Game Sheet v1.0
Bonanza Megaways
Cascade featureDual ReactionsBase game and features
- What starts it
- After a winning combination is resolved.
- What happens to the symbols
- Winning symbols are removed; replacements drop in from above, and the cart reel above reels 2–5 moves right to left to supply more.
- How the sequence develops
- The Reactions continue while replacement symbols form further wins during the same spin or Free Spin.
Sources: Big Time Gaming Launch Article; Big Time Gaming Official Game Page
What starts a cascade?
A win is the usual trigger, but it isn’t the only one. In Gates of Olympus, regular paying symbols start Tumbles; the separate Scatter rule for Free Spins doesn’t make every Scatter appearance a Tumble trigger.
Fire in the Hole 2 uses a Collapsing Mine system. A collapse can follow an ordinary win, but xBomb Wild explosions and Wild Mining can also trigger it. The refill behaviour belongs to the same broad family, even though the starting event can differ.
Are Cascades, Tumbles and Avalanches the same?
They’re names for related remove-and-refill behaviour, not promises that every game follows identical rules. Pragmatic Play calls it a Tumble in Gates of Olympus and Sugar Rush. NetEnt uses Avalanche in Gonzo’s Quest, and ELK uses the same name in Katmandu Gold.
Big Time Gaming’s Dual Reactions changes where the new symbols come from, and Nolimit City’s Collapsing Mine can start without a win at all. So the name alone doesn’t tell you what disappears, where the replacements come from or when it stops.
Do replacement symbols always fall from above?
No. Gates of Olympus and Sugar Rush refill downwards, with symbols dropping into the cleared positions. Extra Chilli doesn’t. Its Dual Reactions bring symbols in from the top and the right, while an extra reel along the bottom moves right to left and feeds symbols upwards.
That’s why “symbols fall from the top” is a good description of some cascades, not a definition of the mechanic.
How long can a cascade continue?
Many sequences continue until a refill produces no further qualifying win. Gonzo’s Quest’s rules say there’s no limit on how many Avalanches can happen in one round, which isn’t the same as long runs being common.
Gates of Olympus keeps tumbling while new wins form, and its UK rules don’t set a cap either. Other games can set their own limits.
Cascades do not decide what makes a win
This is an easy distinction to miss. Fixed Paylines, Ways to Win, Cluster Pays and Pay Anywhere describe how symbols qualify for an award. Cascading Reels describe what the game does afterwards.
Gonzo’s Quest can clear a payline win; Sugar Rush can clear a connected cluster; Gates of Olympus can tumble after a Pay Anywhere win. Same broad continuation idea, different rules for recognising the win.
| Game | Payout system | Cascade label | What the example shows |
|---|---|---|---|
 Gonzo’s Quest |
20 fixed paylines | Avalanche | A payline win starts the Avalanche |
 Gates of Olympus |
Pay Anywhere | Tumble | A win anywhere on screen starts the Tumble |
 Sugar Rush |
Cluster Pays | Tumble | A cluster win starts the Tumble |
 Extra Chilli |
Megaways / Ways | Dual Reactions | New symbols arrive from the top and the right, not just above |
Can cascades increase a multiplier?
Sometimes. Gonzo’s Quest increases its multiplier as Avalanches continue, with a documented x1 to x5 range in the main game and x3 to x15 during Free Falls. That multiplier progression is an extra rule, not something every cascade includes.
Free Falls are also separate from Avalanches. A Free Fall is an awarded free spin, and an Avalanche can unfold inside it. Our Increasing Multipliers guide looks at the multiplier rule itself.
Cascading Reels versus expanding the grid
Replacing symbols in the existing area isn’t the same as opening more playable positions. Yet some games do both. In Fire in the Hole 2, collapses can activate additional rows, taking the active area from three rows to as many as six.
Katmandu Gold pairs its Avalanche with row growth that can reach eight rows during the sequence. The cascade explains how symbols are cleared and replaced; Expanding Reels and win-driven reel expansion explain why there’s more room on the screen.
Cascading Reels FAQ
Is a cascade the same as a free spin?
No. A cascade keeps the current spin or round going after a qualifying result, and any wins along the way still count. Free Spins are separate awarded spins, though a game can run cascades inside them.
Do cascades mean more frequent wins or higher RTP?
The mechanic alone doesn’t tell you either. You need the game’s documented rules and mathematics to assess RTP, volatility or how often wins occur. A multiplier also doesn’t have to increase just because a cascade continues.
Sources reviewed
I checked these games against their own rules, developer game sheets and game pages. Some evidence is only available in-game or through authenticated sources; the public links identify the games.
Big Time Gaming
ELK Studios
NetEnt
Nolimit City
Play’n GO
Pragmatic Play
Where this guide comes from
I compare the game rules for what starts the sequence, what gets removed, how the spaces refill and when it stops. Those details can change between games, even when the developers use the same word for the feature. Read the full research methodology