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.
Cartoon of Dayboro Water Carriers truck spilling water on flooded rural road in rain, cow with umbrella, lily pads in puddles

Dayboro Valley: Flood Probability for March and April 2026

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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