Practical Information for visiting California

Phone coverage is continuous in the cities, along the coast and on the interstates and falls away fast in the Sierra backcountry, the deserts, the redwood country and along Big Sur, where a signal is not to be assumed: download maps before leaving the last town, and treat Caltrans's QuickMap, 511 and the 1-800-427-7623 conditions line as the tools that work when the app does not. Free wifi is standard in cafés, hotels and libraries; the national parks are largely without signal by design; and during a wildfire or a public-safety power shut-off, coverage and charging can both disappear for days, which is the advisories' reason for keeping a charged phone and a paper plan.

Both advisories rate the United States as needing normal precautions. Violent and gun crime rarely touch tourists but the cities have neighbourhoods to avoid, especially from dusk to dawn; petty theft is common in urban centres and tourist spots; and rental cars are the target: never leave bags, passports or valuables in a parked car, even in the boot, because gangs watch for vehicles that look like tourists'. Mass shootings occur and the advisories ask visitors to know how to respond to an active shooter; open carry of firearms is legal in many states. Protests are common and can turn violent; move away at the first sign of trouble.

Nature is the real hazard. Wildfires burn year-round and worst in the dry, hot, windy months; smoke degrades air quality for hundreds of miles; obey every evacuation order. Earthquakes are a risk across California -- two-thirds of the nation's exposure -- so learn the drill. Heat from June to September kills the unprepared in the deserts and the valley, where the Canadian advisory names dehydration and heatstroke as fatal risks. In the mountains, avalanche and weather demand a guide, insurance covering mountain rescue and helicopter evacuation, and a copy of your itinerary left with someone; off-piste skiing can void insurance. Rip currents and cold water take swimmers on the northern coast.

The border: crime linked to drugs is a major issue in the Mexican states across from California, and the advisories caution about hitchhikers and unknown passengers on any crossing.

Dial 911 for an ambulance. Health care is excellent and very expensive: insurance covering treatment and evacuation is essential for non-residents, foreign prescriptions are not valid, and some medicines cannot be brought in, so check the FDA's rules and expect to see a US provider for a refill. The advisories list Zika and West Nile virus as risks, altitude sickness in the high country, rabies possibly present in wildlife including bats, and heat and humidity from June to September as the season's danger; wildfire smoke is a respiratory hazard near active fires. Tap water is safe; the sun at altitude and on the water burns fast; and the deserts require water in quantities visitors rarely carry.

Two sets of laws apply, the state's and the federal, and breaking either can cost a visa. ID: carry a passport showing permission to be in the country; authorities may ask for proof of status at any time. Alcohol is 21 nationwide and checked. Cannabis is legal to buy in California and illegal under federal law: carrying it across a border or onto federal land, national parks included, is a federal offence, previous use can bar entry, and drug paraphernalia is prohibited at the border. Firearms may be openly carried by citizens in many states. Parks are cashless and their food-storage, fire and drone rules are enforced. Driving: right turn on red after stopping unless signed; hire firms' own rules on age and experience.

Manners are informal, first-name and tipped: tipping is expected in restaurants, bars and taxis and to hotel staff, and is how service workers are paid. LGBT+ attitudes vary hugely by state, the UK advisory says; California's are among the most open. Ask before photographing on tribal land.

Emergency numbers: 911 for police, fire and ambulance anywhere in the state; 1-800-427-7623 for Caltrans road conditions; 511 for traveller information.

Consular: Canadian Citizen Services on 1-844-880-6519 or the emergency line 1-888-949-9993, with the Canadian embassy in the federal capital and consulates in the state; the UK's help and services for the US are listed on its advisory. Natural hazards: wildfire with evacuation orders and smoke, earthquakes, extreme heat in the deserts and valley from June to September, winter storms and avalanche in the Sierra, and the Santa Ana and Diablo wind events of autumn; follow local emergency services' instructions and monitor local media.