Read the number. Understand the answer.
21 field guides for the questions behind the data. Start with a topic, then put the explanation to work.
Lake levels
Storage, elevation and recent change.
How to read a reservoir’s percent full
Storage and elevation answer different questions. Use both to understand a reservoir.
Read the guide
Lake Travis: put today’s reading in context
Follow a dated TWDB reading from the headline number to its 30-day chart.
Read the guideTide charts
Plan around high and low water.
How to read a NOAA high and low tide chart
A station, a time zone and a datum make the table meaningful.
Read the guide
Why a nearby tide station can differ from your beach
Follow the water connection and station coverage before trusting a nearby name.
Read the guide
Spring vs neap tides: the difference and how to read your chart
Understand larger and smaller tidal ranges, compare a worked tide-table example, and choose a local NOAA station before planning a visit.
Read the guide
Predicted tide versus observed water: what to check before you go
A tide table estimates the astronomical tide. The water you meet at the shore can be different. Here is how to read the two without confusing either for a safety guarantee.
Read the guideRiver gauges
Find the right station for your stretch.
Gauge height, discharge and flood stage
Three different quantities that should never be read as interchangeable.
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Which Susquehanna gauge should you use?
Begin with your river reach and confirm the station on the source map.
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Why a USGS river reading can change after you save it
A provisional observation is useful information with a review still ahead. Learn what can change, how to cite a reading and what a gap does—and does not—mean.
Read the guideRadon zones
Understand the county behind a ZIP area.
EPA radon zones versus a home test
A county-level potential category cannot measure the air inside a home.
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Why a ZIP-area search can return multiple counties
The lookup uses Census geography, with boundaries and relationships that need explanation.
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When should you test for radon again? A practical home checklist
A past low result is useful, but changes to a home or how it is used can make a new test worth discussing. Use this checklist to find the right next question.
Read the guideFlood maps
Find an official FEMA map and read its zones with care.
GS pay
Grade, step and locality, clearly explained.
Electricity costs
Estimate appliance use and compare published state averages.
How to calculate electricity cost from watts and hours
Calculate daily and monthly appliance costs, avoid the cents-versus-dollars error, and compare your own tariff with dated EIA state averages.
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Your electricity bill versus a state average: why the numbers differ
A state average is useful context, but it is not your tariff. Separate usage, variable rates and fixed charges before comparing an estimate with a real bill.
Read the guideBurn bans
Find the issuing authority and current order.
How to verify a Texas county burn ban
Use the map to find the county, then read the current issuing authority’s information.
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Wildfire danger versus a legal burn ban
Weather conditions and legal restrictions answer different questions.
Read the guideHail records
Explore reports with dates and source context.
