Does Dayboro flood in March and April?

March is statistically Dayboro's wettest month, averaging 168.2 mm of rainfall, making it the highest-risk period for flooding in the valley. The Stanley River system and fast-rising tributaries like Laceys Creek and Kobble Creek can cut road access within hours of heavy rain. April sees a sharp drop to roughly 86 mm on average, but residual soil saturation from March can still produce flash flooding on already-wet catchments.

Why does Dayboro get cut off during floods?

Dayboro sits in the Stanley River valley with all access roads u2014 Old Gympie Road, Laceys Creek Road, Kobble Creek Road, and Dayboro-Woodford Road u2014 crossing creek lines that rise rapidly under heavy rain. The surrounding catchments are steep and fast-draining, meaning creeks can become impassable within hours. When the Stanley River is already running high, these tributaries have nowhere to drain, and roads stay cut for extended periods, effectively turning Dayboro into an island.

Do Wivenhoe and Somerset dams protect Dayboro from flooding?

No. Wivenhoe Dam and Somerset Dam protect Brisbane downstream, but Dayboro sits upstream of both dams. When the Stanley River rises due to heavy rainfall in the Conondale Ranges, Dayboro experiences flooding before the water even reaches the dam system. The dams provide zero flood mitigation for the Dayboro valley itself.

What causes major floods in the Dayboro and Stanley River area?

Major floods in the Stanley River catchment are driven by intense rainfall over the Conondale Ranges, where orographic lift forces moisture-laden air upward, generating extreme localised rainfall. East coast lows, La Niu00f1a seasons, and active phases of the Madden-Julian Oscillation (MJO) all increase the likelihood of sustained heavy rain. When these weather systems hit already-saturated soils, runoff is rapid and creek levels rise quickly across the Dayboro valley.

How full are Wivenhoe and Somerset dams in 2026?

As of 8 March 2026, Wivenhoe Dam was at 77.0% of water supply capacity (897,399 ML of 1,165,240 ML) and Somerset Dam was at 78.2% (297,182 ML of 379,849 ML), with flood storage compartments 100% available in both dams. This means significant buffer capacity exists for downstream Brisbane, though these levels have no bearing on upstream flood risk for Dayboro residents.

Flood probability march/april 2026

A data-driven flood risk assessment for Dayboro Valley covering March and April 2026, drawing on Stanley River history, current dam levels, La Niña conditions, and the Inigo Jones analytical framework.

Dayboro Valley: Flood Probability for March and April 2026

Dayboro Weather Research • 8 March 2026 • Deep Research Report • Members Only

Abstract

March is statistically Dayboro’s wettest month. Combined with residual La Niña soil moisture, an active Madden-Julian Oscillation, and Solar Cycle 25 in its post-peak declining phase, the next four to six weeks represent the period of highest flood risk for the 2026 season. This report analyses the historical Stanley River flood record, current ocean-atmosphere conditions, East Coast Low risk for autumn 2026, and the Inigo Jones solar cycle framework. It provides a risk table with current dam levels and a practical monitoring guide for Dayboro residents.

168 mm
March average rainfall
(highest month of year)

9.77 m
Stanley River peak at
Woodford, February 2022

100%
Dam flood storage available
both Wivenhoe & Somerset

March is statistically Dayboro’s wettest month of the year. That’s a fact worth taking seriously — not because it guarantees a flood, but because floods are almost always born from wet months on already-saturated soil, and right now, the soil is wet.

This year, March arrives with the tail end of a La Niña season, an active Madden-Julian Oscillation feeding tropical moisture into southeast Queensland, and Solar Cycle 25 just past its peak. The La Niña is weakening. The MJO signal is transient. The solar cycle is background context, not a trigger. None of these factors alone makes 2026 a major flood year. Together, they make the next four weeks worth watching closely.

Dayboro sits upstream of both Somerset Dam and Wivenhoe Dam. Those dams protect Brisbane. They do not protect Dayboro. When the Stanley River rises at Woodford, the valley feels it first...

This report covers:

Why Dayboro floods the way it does — geography and orographic lift explained
The full Stanley River flood record: 1893, 1974, 2011, 2022, Alfred 2025
The Inigo Jones solar cycle framework — what it says, what it doesn’t
East Coast Lows: the overlooked March–April flood driver
Current conditions: La Niña status, MJO, March 2026 BOM outlooks
Live dam storage levels: Wivenhoe 77%, Somerset 78% (both with 100% flood storage available)
Onflow effects: road isolation, emergency access, agricultural impact
A 9-factor risk assessment table with current state ratings
A practical monitoring guide: what to watch and where to find it

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This deep-research report is available to Dayboro.au members. Membership gives you access to all research posts, extended weather analysis, and our long-range forecast archive.

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