Use hazard records without promising exact predictions

What can past flood observations tell a town about future risk?

Submit: An evidence record, explanation and revision.

Related lesson: Weather Systems

This is a teacher-led extension beyond the short lesson. The task supplies a performance opportunity; completion alone does not certify mastery, full NGSS coverage or state alignment.

Build the idea

Hazard data reveal patterns that can guide forecasts and mitigation. A past frequency is not a schedule, and records have uncertainty. Flood barriers, warning systems and land-use changes can reduce particular risks while introducing costs or shifting impacts. Earthquake occurrence cannot currently be predicted with an exact date, place and magnitude.

Evidence and model inputs

Invented town record: 20 years observed; five years had river levels above a low-road threshold and two above a high-building threshold. Events overlap: the two high-building years are included in the five low-road years. Proposed actions: elevate the low road, improve warnings, or move critical equipment upstairs. The short record is stationary only as an explicit modeling assumption.

Keep actual observations, published findings and invented model cases labeled separately. If a source or required equipment is unavailable, pause that part with a teacher; do not invent results.

Materials and preparation

Paper, graph paper or spreadsheet, and the linked readings.

Grade-level scope

Use data to forecast hazards and inform mitigation; do not claim exact earthquake prediction.

Do the work

1. Calculate observed threshold frequencies without double-counting overlapping events.
2. Plot thresholds and write a forecast statement using uncertainty rather than a guaranteed date.
3. Read the USGS prediction explanation and compare probabilistic hazard assessment with exact prediction.
4. Choose two mitigation actions and explain the hazard pathway each addresses, costs and remaining risk.
5. Identify how changing rainfall, development or a longer record could alter the estimate.

Learner worksheet

Write on paper or type here and print. Entries stay in this page’s memory and are lost when you leave or reload; they are not saved or submitted.

Check your reasoning

1. What fraction exceeded the low-road threshold?
2. Were there seven separate flood years?
3. Does one event every four years mean a four-year schedule?
4. Can a barrier remove all risk?

Teacher review guide

Review the actual deliverable and discuss the reasoning. For each criterion, use 0 when evidence is absent or fundamentally incorrect, 1 when partly supported with a material error or omission, and 2 when accurate, supported and complete for the stated task. Maximum 8 points is a task score, not a proficiency certification. Give feedback and allow revision.

1. Analyzes frequency and overlapping records correctly.
2. Uses uncertainty in a forecast.
3. Links mitigation to evidence and mechanisms.
4. Distinguishes risk assessment from exact prediction.

Sources and standard reference

• Official NGSS MS-ESS3-2 performance expectation — inspect the practice, core idea, crosscutting concept and assessment boundary.
• USGS: earthquake prediction

Instructional text and hypothetical cases are original. Linked source readings supply published evidence where specified. Teachers should judge fit with their course and state requirements.