Hazard Areas

Hazard areas are thematic layers that should have color ramps that pertain to the type of risk involved. For example, a ramp for a fire hazard layer should have red/orange tones, and a ramp for a sea level rise layer should have blue tones.

Our existing layer styles should be used as a model for new hazard layers.

Examples

Fire Hazard

Fill:

FF7F0E	D33115	9F0500

Opacity: 60%

Fire Hazard Severity Zones

Sea Level Rise

Fill:

BBDEFB	64B5F6	2196F3	1976D2	0D47A1

Opacity: 80%

CalFloD-3D 1.41m Sea Level Rise

Probabilistic Earthquake Hazard

Fill:

EEF1EA	E6CC93	8C5109

Opacity: 80%

Probabilistic Earthquake Hazard Map

Storm Surge

Fill:

F6FBEE	D5EDD0	ABDCB6	71C4BC	399CC0	0C6AA5	003973

Opacity: 80%

Category 5 Storm Surge Hazard Maps

Combining hazard layers

When showing multiple hazard layers on the same map, be sure that the colors are clearly distinguishable from one another so the viewer is not confused about which layer they are looking at. Adding a legend for clarity is also a best practice.

Alternate ramp colors

Many hazard layers share thematic similarities — for example, Sea Level Rise Risk, Flood Risk, Storm Surge, and Liquefaction are all water-related hazards. Because default color ramps are thematically determined, when showing layers in conjunction with one another, it is sometimes necessary to deviate from default color ramps in order to provide visual distinction between different layers.

The simplest method to deviate from the default color theme is to shift one step in either direction on the color wheel. For example, if the default ramp is primarily blue, try an alternate color ramp that is green or purple. Below, we show alternate ramps for the Storm Surge layer.

Example: Category 5 Storm Surge

Default Ramp

Fill:

F6FBEE	D5EDD0	ABDCB6	71C4BC	399CC0	0C6AA5	003973

Opacity: 80%

Alternate Ramp - Purple

Fill:

F7FCFD	D5E3EF	AAC3DE	8F95C6	8A5DAA	812186	4D004B

Opacity: 80%

Alternate Ramp - Green

Fill:

F5EFF6	D0D1E4	AABCD8	75A8CB	448E97	2E6A5A

Opacity: 80%